AD ADUC836 Microconverter, dual 16-bit/24- bit adcs with embedded 62 kb flash mcu Datasheet

a
MicroConverter ®, Dual 16-Bit/24-Bit -
ADCs with Embedded 62 kB Flash MCU
ADuC834
FEATURES
High Resolution - ADCs
2 Independent ADCs (16-Bit and 24-Bit Resolution)
24-Bit No Missing Codes, Primary ADC
21-Bit rms (18.5-Bit p-p) Effective Resolution @ 20 Hz
Offset Drift 10 nV/C, Gain Drift 0.5 ppm/C
Memory
62 Kbytes On-Chip Flash/EE Program Memory
4 Kbytes On-Chip Flash/EE Data Memory
Flash/EE, 100 Year Retention, 100 Kcycles Endurance
3 Levels of Flash/EE Program Memory Security
In-Circuit Serial Download (No External Hardware)
High Speed User Download (5 Seconds)
2304 Bytes On-Chip Data RAM
8051-Based Core
8051 Compatible Instruction Set
32 kHz External Crystal
On-Chip Programmable PLL (12.58 MHz Max)
3 16-Bit Timer/Counter
26 Programmable I/O Lines
11 Interrupt Sources, Two Priority Levels
Dual Data Pointer, Extended 11-Bit Stack Pointer
On-Chip Peripherals
Internal Power on Reset Circuit
12-Bit Voltage Output DAC
Dual 16-Bit - DACs/PWMs
On-Chip Temperature Sensor
Dual Excitation Current Sources
Time Interval Counter (Wake-Up/RTC Timer)
UART, SPI®, and I2C ® Serial I/O
High Speed Baud Rate Generator (Including 115,200)
Watchdog Timer (WDT)
Power Supply Monitor (PSM)
Power
Normal: 2.3 mA Max @ 3.6 V (Core CLK = 1.57 MHz)
Power-Down: 20 A Max with Wake-Up Timer Running
Specified for 3 V and 5 V Operation
Package and Temperature Range
52-Lead MQFP (14 mm 14 mm), –40C to +125C
56-Lead LFCSP (8 mm 8 mm), –40C to +85C
APPLICATIONS
Intelligent Sensors
Weigh Scales
Portable Instrumentation, Battery-Powered Systems
4–20 mA Transmitters
Data Logging
Precision System Monitoring
FUNCTIONAL BLOCK DIAGRAM
AVDD
ADuC834
AVDD
CURRENT
SOURCE
AIN1
AIN2
AIN3
AIN4
BUF
MUX
PGA
PRIMARY
24-BIT - ADC
AGND
AUXILIARY
16-BIT - ADC
MUX
AIN5
REFIN–
EXTERNAL
VREF
DETECT
INTERNAL
BAND GAP
VREF
RESET
DVDD
PLL AND PROG
CLOCK DIV
OSC
IEXC2
DAC
PWM0
MUX
PWM1
8051-BASED MCU WITH ADDITIONAL
PERIPHERALS
62 KBYTES FLASH/EE PROGRAM MEMORY
4 KBYTES FLASH/EE DATA MEMORY
2304 BYTES USER RAM
POR
DGND
DUAL
16-BIT
- DAC
BUF
DUAL
16-BIT
PWM
TEMP
SENSOR
REFIN+
12-BIT
DAC
IEXC1
WAKE- UP/
RTC TIMER
3 16 BIT TIMERS
BAUD R ATE TIMER
POWER SUPPLY MON
WATCHDOG TIMER
4 PARALLEL
PORTS
UART, SPI, AND I2C
SERIAL I/O
XTAL1 XTAL2
GENERAL DESCRIPTION
The ADuC834 is a complete smart transducer front end,
integrating two high resolution - ADCs, an 8-bit MCU, and
program/data Flash/EE memory on a single chip.
The two independent ADCs (primary and auxiliary) include a
temperature sensor and a PGA (allowing direct measurement of
low level signals). The ADCs with on-chip digital filtering and
programmable output data rates are intended for the measurement
of wide dynamic range, low frequency signals, such as those in
weigh scale, strain-gage, pressure transducer, or temperature
measurement applications.
The device operates from a 32 kHz crystal with an on-chip PLL
generating a high frequency clock of 12.58 MHz. This clock is
routed through a programmable clock divider from which the MCU
core clock operating frequency is generated. The microcontroller
core is an 8052 and therefore 8051 instruction set compatible
with 12 core clock periods per machine cycle.
62 Kbytes of nonvolatile Flash/EE program memory, 4 Kbytes of
nonvolatile Flash/EE data memory, and 2304 bytes of data RAM
are provided on-chip. The program memory can be configured
as data memory to give up to 60 Kbytes of NV data memory in
data logging applications.
On-chip factory firmware supports in-circuit serial download and
debug modes (via UART), as well as single-pin emulation mode
via the EA pin. The ADuC834 is supported by a QuickStart™
development system featuring low cost software and hardware
development tools.
REV. A
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties that
may result from its use. No license is granted by implication or otherwise
under any patent or patent rights of Analog Devices. Trademarks and
registered trademarks are the property of their respective companies.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700
www.analog.com
Fax: 781/326-8703
© 2003 Analog Devices, Inc. All rights reserved.
ADuC834
TABLE OF CONTENTS
FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
APPLICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
FUNCTIONAL BLOCK DIAGRAM . . . . . . . . . . . . . . . . . 1
GENERAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . 1
SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
ABSOLUTE MAXIMUM RATINGS . . . . . . . . . . . . . . . . 9
ORDERING GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
PIN CONFIGURATIONS . . . . . . . . . . . . . . . . . . . . . . . . . 9
DETAILED BLOCK DIAGRAM . . . . . . . . . . . . . . . . . . 10
PIN FUNCTION DESCRIPTIONS . . . . . . . . . . . . . . . . 10
MEMORY ORGANIZATION . . . . . . . . . . . . . . . . . . . . . 13
SPECIAL FUNCTION REGISTERS (SFRS) . . . . . . . .
Accumulator (ACC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
B SFR (B) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Data Pointer (DPTR) . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stack Pointer (SP and SPH) . . . . . . . . . . . . . . . . . . . . . .
Program Status Word (PSW) . . . . . . . . . . . . . . . . . . . . . .
Power Control SFR (PCON) . . . . . . . . . . . . . . . . . . . . . .
ADuC834 Configuration SFR (CFG834) . . . . . . . . . . . .
Complete SFR Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ADC SFR INTERFACE
ADCSTAT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ADCMODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ADC0CON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ADC1CON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ADC0H/ADC0M/ADC0L/ADC1H/ADC1L . . . . . . . . . .
OF0H/OF0M/OF0L/OF1H/OF1L . . . . . . . . . . . . . . . . .
GN0H/GN0M/GN0L/GN1H/GN1L . . . . . . . . . . . . . . . .
SF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ICON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14
14
14
14
15
15
15
15
16
17
18
19
19
20
20
20
21
21
PRIMARY AND AUXILIARY ADC NOISE
PERFORMANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
PRIMARY AND AUXILIARY ADC CIRCUIT
DESCRIPTION
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Primary ADC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Auxiliary ADC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Analog Input Channels . . . . . . . . . . . . . . . . . . . . . . . . . .
Primary and Auxiliary ADC Inputs . . . . . . . . . . . . . . . . .
Analog Input Ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Programmable Gain Amplifier . . . . . . . . . . . . . . . . . . . . .
Bipolar/Unipolar Inputs . . . . . . . . . . . . . . . . . . . . . . . . . .
Reference Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Burnout Currents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Excitation Currents . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Reference Detect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
- Modulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Digital Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ADC Chopping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
23
23
24
24
25
25
25
25
26
26
26
26
26
27
28
28
NONVOLATILE FLASH/EE MEMORY
Flash/EE Memory Overview . . . . . . . . . . . . . . . . . . . . . .
Flash/EE Memory and the ADuC834 . . . . . . . . . . . . . . .
ADuC834 Flash/EE Memory Reliability . . . . . . . . . . . . .
Flash/EE Program Memory . . . . . . . . . . . . . . . . . . . . . . .
Serial Downloading . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Parallel Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . .
User Download Mode (ULOAD) . . . . . . . . . . . . . . . . . .
Flash/EE Program Memory Security . . . . . . . . . . . . . . . .
Lock, Secure, and Serial Safe Modes . . . . . . . . . . . . . . . .
Using the Flash/EE Data Memory . . . . . . . . . . . . . . . . . .
ECON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Programming the Flash/EE Data Memory . . . . . . . . . . . .
Flash/EE Memory Timing . . . . . . . . . . . . . . . . . . . . . . . .
28
28
29
30
30
30
30
31
31
31
32
33
33
OTHER ON-CHIP PERIPHERALS
DAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pulsewidth Modulator (PWM) . . . . . . . . . . . . . . . . . . . . .
On-Chip PLL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Time Interval Counter (Wake-Up/RTC Timer) . . . . . . . .
Watchdog Timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Supply Monitor . . . . . . . . . . . . . . . . . . . . . . . . . . .
Serial Peripheral Interface (SPI) . . . . . . . . . . . . . . . . . . . .
I2C Serial Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Dual Data Pointer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
34
36
39
40
42
43
44
46
48
8052 COMPATIBLE ON-CHIP PERIPHERALS
Parallel I/O Ports 0–3 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Timers/Counters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UART Serial Interface . . . . . . . . . . . . . . . . . . . . . . . . . . .
UART Operating Modes . . . . . . . . . . . . . . . . . . . . . . . . .
Baud Rate Generation Using Timer 1 and Timer 2 . . . . .
Baud Rate Generation Using Timer 3 . . . . . . . . . . . . . . .
Interrupt System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
49
52
57
57
59
60
61
HARDWARE DESIGN CONSIDERATIONS
External Memory Interface . . . . . . . . . . . . . . . . . . . . . . .
Power Supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power-On Reset (POR) Operation . . . . . . . . . . . . . . . . . .
Power Consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Saving Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Wake-Up from Power-Down Latency . . . . . . . . . . . . . . .
Grounding and Board Layout Recommendations . . . . . .
ADuC834 System Self-Identification . . . . . . . . . . . . . . . .
Clock Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
63
64
64
64
65
65
65
66
66
OTHER HARDWARE CONSIDERATIONS
In-Circuit Serial Download Access . . . . . . . . . . . . . . . . .
Embedded Serial Port Debugger . . . . . . . . . . . . . . . . . . .
Single-Pin Emulation Mode . . . . . . . . . . . . . . . . . . . . . . .
Typical System Configuration . . . . . . . . . . . . . . . . . . . . .
67
67
67
68
QUICKSTART DEVELOPMENT SYSTEM . . . . . . . . . 69
TIMING SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . 70
OUTLINE DIMENSIONS . . . . . . . . . . . . . . . . . . . . . . . . 80
–2–
REV. A
SPECIFICATIONS1
(AVDD = 2.7 V to 3.6 V or 4.75 V to 5.25 V, DVDD = 2.7 V to 3.6 V or 4.75 V to
5.25 V, REFIN(+) = 2.5 V, REFIN(–) = AGND; AGND = DGND = 0 V; XTAL1/XTAL2 =
32.768 kHz Crystal; all specifications TMIN, to TMAX unless otherwise noted.)
Parameter
ADC SPECIFICATIONS
Conversion Rate
Primary ADC
No Missing Codes2
Resolution
Output Noise
Integral Nonlinearity
Offset Error3
Offset Error Drift
Full-Scale Error4
Gain Error Drift5
ADC Range Matching
Power Supply Rejection (PSR)
Common-Mode DC Rejection
On AIN
ADuC834
Test Conditions/Comments
Unit
5.4
105
On Both Channels
Programmable in 0.732 ms Increments
Hz min
Hz max
24
13.5
18.5
See Tables X and XI
in ADuC834 ADC
Description
± 15
±3
± 10
± 10
± 0.5
±2
113
80
20 Hz Update Rate
Range = ± 20 mV, 20 Hz Update Rate
Range = ± 2.56 V, 20 Hz Update Rate
Output Noise Varies with Selected
Update Rate and Gain Range
Bits min
Bits p-p typ
Bits p-p typ
1 LSB16
ppm of FSR max
V typ
nV/°C typ
V typ
ppm/°C typ
V typ
dBs typ
dBs min
95
113
125
At DC, AIN = 7.8 mV, Range = ± 20 mV
At DC, AIN = 1 V, Range = ± 2.56 V
At DC, AIN = 1 V, Range = ± 2.56 V
20 Hz Update Rate
50 Hz/60 Hz ± 1 Hz, AIN = 7.8 mV,
Range = ± 20 mV
50 Hz/60 Hz ± 1 Hz, AIN = 1 V,
Range = ± 2.56 V
50 Hz/60 Hz ± 1 Hz, AIN = 1 V,
Range = ± 2.56 V
On REFIN
Common-Mode 50 Hz/60 Hz Rejection2
On AIN
95
90
On REFIN
Normal Mode 50 Hz/60 Hz Rejection2
On AIN
On REFIN
Auxiliary ADC
No Missing Codes2
Resolution
Output Noise
Integral Nonlinearity
Offset Error3
Offset Error Drift
Full-Scale Error6
Gain Error Drift5
Power Supply Rejection (PSR)
Normal Mode 50 Hz/60 Hz Rejection2
On AIN
On REFIN
DAC PERFORMANCE
DC Specifications7
Resolution
Relative Accuracy
Differential Nonlinearity
Offset Error
Gain Error8
AC Specifications2, 7
Voltage Output Settling Time
Digital-to-Analog Glitch Energy
REV. A
ADuC834
90
AIN = 18 mV
AIN = 7.8 mV, Range = ± 20 mV
AIN = 1 V, Range = ± 2.56 V
50 Hz/60 Hz ± 1 Hz, 20 Hz Update Rate
50 Hz/60 Hz ± 1 Hz, 20 Hz Update Rate
60
60
16
16
See Table XII in
ADuC834 ADC
Description
± 15
–2
1
–2.5
± 0.5
80
Range = ± 2.5 V, 20 Hz Update Rate
Output Noise Varies with Selected
Update Rate
60
60
dBs min
dBs typ
dBs typ
dBs min
dBs min
dBs min
dBs min
dBs min
Bits min
Bits p-p typ
AIN = 1 V, 20 Hz Update Rate
ppm of FSR max
LSB typ
V/°C typ
LSB typ
ppm/°C typ
dBs min
50 Hz/60 Hz ± 1 Hz
50 Hz/60 Hz ± 1 Hz, 20 Hz Update Rate
dBs min
dBs min
12
±3
–1
± 50
±1
±1
AVDD Range
VREF Range
Bits
LSB typ
LSB max
mV max
% max
% typ
15
10
Settling Time to 1 LSB of Final Value
1 LSB Change at Major Carry
s typ
nVs typ
Guaranteed 12-Bit Monotonic
–3–
ADuC834
SPECIFICATIONS (continued)
Parameter
INTERNAL REFERENCE
ADC Reference
Reference Voltage
Power Supply Rejection
Reference Tempco
DAC Reference
Reference Voltage
Power Supply Rejection
Reference Tempco
ADuC834
Test Conditions/Comments
Unit
1.25 ± 1%
45
100
Initial Tolerance @ 25°C, VDD = 5 V
V min/max
dBs typ
ppm/°C typ
2.5 ± 1%
50
± 100
Initial Tolerance @ 25°C, VDD = 5 V
V min/max
dBs typ
ppm/°C typ
ANALOG INPUTS/REFERENCE INPUTS
Primary ADC
Differential Input Voltage Ranges9, 10
Bipolar Mode (ADC0CON3 = 0)
Analog Input Current2
Analog Input Current Drift
Absolute AIN Voltage Limits2
Auxiliary ADC
Input Voltage Range9, 10
Average Analog Input Current
Average Analog Input Current Drift2
Absolute AIN Voltage Limits2, 11
External Reference Inputs
REFIN(+) to REFIN(–) Range2
Average Reference Input Current
Average Reference Input Current Drift
‘NO Ext. REF’ Trigger Voltage
ADC SYSTEM CALIBRATION
Full-Scale Calibration Limit
Zero-Scale Calibration Limit
Input Span
ANALOG (DAC) OUTPUT
Voltage Range
Resistive Load
Capacitive Load
Output Impedance
ISINK
TEMPERATURE SENSOR
Accuracy
Thermal Impedance (JA)
± 20
± 40
± 80
± 160
± 320
± 640
± 1.28
± 2.56
±1
±5
±5
± 15
AGND + 100 mV
AVDD – 100 mV
0 to VREF
External Reference Voltage = 2.5 V
RN2, RN1, RN0 of ADC0CON Set to
0 0 0 (Unipolar Mode 0 mV to 20 mV)
0 0 1 (Unipolar Mode 0 mV to 40 mV)
0 1 0 (Unipolar Mode 0 mV to 80 mV)
0 1 1 (Unipolar Mode 0 mV to 160 mV)
1 0 0 (Unipolar Mode 0 mV to 320 mV)
1 0 1 (Unipolar Mode 0 mV to 640 mV)
1 1 0 (Unipolar Mode 0 V to 1.28 V)
1 1 1 (Unipolar Mode 0 V to 2.56 V)
TMAX = 85°C
TMAX = 125°C
TMAX = 85°C
TMAX = 125°C
mV
mV
mV
mV
mV
mV
V
V
nA max
nA max
pA/°C typ
pA/°C typ
V min
V max
Unipolar Mode, for Bipolar Mode
V
See Note 11
Input Current Will Vary with Input
nA/V typ
Voltage on the Unbuffered Auxiliary ADC pA/V/°C typ
V min
V max
125
±2
AGND – 30 mV
AVDD + 30 mV
1
AVDD
1
± 0.1
0.3
0.65
Both ADCs Enabled
NOXREF Bit Active if VREF < 0.3 V
NOXREF Bit Inactive if VREF > 0.65 V
+1.05 FS
–1.05 FS
0.8 FS
2.1 FS
V min
V max
A/V typ
nA/V/°C typ
V min
V max
V max
V min
V min
V max
0 to VREF
0 to AVDD
10
100
0.5
50
DACRN = 0 in DACCON SFR
DACRN = 1 in DACCON SFR
From DAC Output to AGND
From DAC Output to AGND
±2
90
52
MQFP Package
CSP Package (Base Floating)12
–4–
V typ
V typ
kΩ typ
pF typ
Ω typ
A typ
°C typ
°C/W typ
°C/W typ
REV. A
ADuC834
Parameter
ADuC834
TRANSDUCER BURNOUT CURRENT SOURCES
AIN+ Current
–100
AIN– Current
+100
Initial Tolerance @ 25°C
Drift
± 10
0.03
EXCITATION CURRENT SOURCES
Output Current
Initial Tolerance @ 25°C
Drift
Initial Current Matching @ 25°C
Drift Matching
Line Regulation (AVDD)
Load Regulation
Output Compliance2
LOGIC INPUTS
All Inputs Except SCLOCK, RESET,
and XTAL12
VINL, Input Low Voltage
VINH, Input High Voltage
SCLOCK and RESET Only
(Schmitt-Triggered Inputs)2
VT+
VT–
VT+ – VT–
Input Currents
Port 0, P1.2–P1.7, EA
SCLOCK, MOSI, MISO, SS13
RESET
P1.0, P1.1, Ports 2 and 3
Input Capacitance
Unit
AIN+ Is the Selected Positive Input to
the Primary ADC
AIN– Is the Selected Negative Input to
the Auxiliary ADC
nA typ
nA typ
% typ
%/°C typ
A typ
% typ
ppm/°C typ
% typ
ppm/°C typ
A/V typ
A/V typ
V max
min
–200
± 10
200
±1
20
1
0.1
AVDD – 0.6
AGND
Available from Each Current Source
0.8
0.4
2.0
DVDD = 5 V
DVDD = 3 V
V max
V max
V min
1.3/3
0.95/2.5
0.8/1.4
0.4/1.1
0.3/0.85
0.3/0.85
DVDD = 5 V
DVDD = 3 V
DVDD = 5 V
DVDD = 3 V
DVDD = 5 V
DVDD = 3 V
V min/V max
V min/V max
V min/V max
V min/V max
V min/V max
V min/V max
± 10
–10 min, –40 max
± 10
± 10
35 min, 105 max
± 10
–180
–660
–20
–75
5
VIN = 0 V or VDD
VIN = 0 V, DVDD = 5 V, Internal Pull-Up
VIN = VDD, DVDD = 5 V
VIN = 0 V, DVDD = 5 V
VIN = VDD, DVDD = 5 V, Internal Pull-Down
VIN = VDD, DVDD = 5 V
VIN = 2 V, DVDD = 5 V
A max
A min/A max
A max
A max
A min/A max
A max
A min
A max
A min
A max
pF typ
Matching between Both Current Sources
AVDD = 5 V + 5%
CRYSTAL OSCILLATOR (XTAL1 AND XTAL2)
Logic Inputs, XTAL1 Only2
VINL, Input Low Voltage
0.8
0.4
VINH, Input High Voltage
3.5
2.5
XTAL1 Input Capacitance
18
XTAL2 Output Capacitance
18
REV. A
Test Conditions/Comments
VIN = 450 mV, DVDD = 5 V
All Digital Inputs
DVDD = 5 V
DVDD = 3 V
DVDD = 5 V
DVDD = 3 V
–5–
V max
V max
V min
V min
pF typ
pF typ
ADuC834
SPECIFICATIONS (continued)
Parameter
ADuC834
Test Conditions/Comments
Unit
VOL, Output Low Voltage14
2.4
2.4
0.4
V min
V min
V max
Floating State Leakage Current2
Floating State Output Capacitance
0.4
0.4
± 10
5
VDD = 5 V, ISOURCE = 80 A
VDD = 3 V, ISOURCE = 20 A
ISINK = 8 mA, SCLOCK,
MOSI/SDATA
ISINK = 10 mA, P1.0 and P1.1
ISINK = 1.6 mA, All Other Outputs
2.63
4.63
± 3.0
± 4.0
2.63
4.63
± 3.0
± 4.0
Four Trip Points Selectable in This Range
Programmed via TPA1–0 in PSMCON
TMAX = 85°C
TMAX = 125°C
Four Trip Points Selectable in This Range
Programmed via TPD1–0 in PSMCON
TMAX = 85C
TMAX = 125C
V min
V max
% max
% max
V min
V max
% max
% max
0
2000
Nine Timeout Periods in This Range
Programmed via PRE3–0 in WDCON
ms min
ms max
98.3
Clock Rate Generated via On-Chip PLL
Programmable via CD2–0 Bits in
PLLCON SFR
kHz min
2
LOGIC OUTPUTS (Not Including XTAL2)
VOH, Output High Voltage
POWER SUPPLY MONITOR (PSM)
AVDD Trip Point Selection Range
AVDD Power Supply Trip Point Accuracy
DVDD Trip Point Selection Range
DVDD Power Supply Trip Point Accuracy
WATCHDOG TIMER (WDT)
Timeout Period
MCU CORE CLOCK RATE
MCU Clock Rate2
START-UP TIME
At Power-On
After External RESET in Normal Mode
After WDT Reset in Normal Mode
From Idle Mode
From Power-Down Mode
Oscillator Running
Wake-Up with INT0 Interrupt
Wake-Up with SPI Interrupt
Wake-Up with TIC Interrupt
Wake-Up with External RESET
Oscillator Powered Down
Wake-Up with INT0 Interrupt
Wake-Up with SPI Interrupt
Wake-Up with External RESET
V max
V max
A max
pF typ
12.58
MHz max
300
3
3
10
ms typ
ms typ
ms typ
s typ
Controlled via WDCON SFR
OSC_PD Bit = 0 in PLLCON SFR
s typ
s typ
s typ
ms typ
20
20
20
3
OSC_PD Bit = 1 in PLLCON SFR
s typ
s typ
ms typ
20
20
5
FLASH/EE MEMORY RELIABILITY CHARACTERISTICS15
Endurance16
100,000
Data Retention17
100
–6–
Cycles min
Years min
REV. A
ADuC834
Parameter
POWER REQUIREMENTS
Power Supply Voltages
AVDD, 3 V Nominal Operation
AVDD, 5 V Nominal Operation
DVDD, 3 V Nominal Operation
DVDD, 5 V Nominal Operation
5 V POWER CONSUMPTION
Power Supply Currents Normal Mode18, 19
DVDD Current
DVDD Current
AVDD Current
Typical Additional Power Supply Currents
(AIDD and DIDD)
PSM Peripheral
Primary ADC
Auxiliary ADC
DAC
Dual Current Sources
3 V POWER CONSUMPTION
Power Supply Currents Normal Mode18, 19
DVDD Current
DVDD Current
AVDD Current
ADuC834
Test Conditions/Comments
DVDD and AVDD Can Be Set Independently
2.7
3.6
4.75
5.25
2.7
3.6
4.75
5.25
V min
V max
V min
V max
V min
V max
V min
V max
DVDD = 4.75 V to 5.25 V, AVDD = 5.25 V
4
13
16
180
Core CLK = 1.57 MHz
Core CLK = 12.58 MHz
Core CLK = 12.58 MHz
Core CLK = 1.57 MHz or 12.58 MHz
Core CLK = 1.57 MHz
mA max
mA typ
mA max
A max
A typ
mA typ
A typ
A typ
A typ
50
1
500
150
400
DVDD = 2.7 V to 3.6 V
2.3
8
10
180
Core CLK = 1.57 MHz
Core CLK = 12.58 MHz
Core CLK = 12.58 MHz
AVDD = 5.25 V, Core CLK = 1.57 MHz
or 12.58 MHz
Core CLK = 1.57 MHz or 12.58 MHz
TMAX = 85°C; Osc. On, TIC On
TMAX = 125°C; Osc. On, TIC On
Osc. Off
AVDD = 5.25 V; TMAX = 85°C; Osc.
On or Osc. Off
AVDD = 5.25 V; TMAX = 125°C; Osc.
On or Osc. Off
Power Supply Currents Power-Down Mode18, 19
20
DVDD Current
40
10
DVDD Current
1
AVDD Current
3
REV. A
Unit
–7–
mA max
mA typ
mA max
A max
A max
A max
A typ
A max
A max
ADuC834
NOTES
1
Temperature Range for ADuC834BS (MQFP package) is –40°C to +125°C.
Temperature Range for ADuC834BCP (CSP package) is –40°C to +85°C.
2
These numbers are not production tested but are guaranteed by design and/or characterization data on production release.
3
System Zero-Scale Calibration can remove this error.
4
The primary ADC is factory calibrated at 25°C with AVDD = DVDD = 5 V yielding this full-scale error of 10 V. If user power supply or temperature conditions are
significantly different from these, an Internal Full-Scale Calibration will restore this error to 10 V. A system zero-scale and full-scale calibration will remove this
error altogether.
5
Gain Error Drift is a span drift. To calculate Full-Scale Error Drift, add the Offset Error Drift to the Gain Error Drift times the full-scale input.
6
The auxiliary ADC is factory calibrated at 25°C with AVDD = DVDD = 5 V yielding this full-scale error of –2.5 LSB. A system zero-scale and full-scale calibration
will remove this error altogether.
7
DAC linearity and ac specifications are calculated using: reduced code range of 48 to 4095, 0 to V REF; reduced code range of 100 to 3950, 0 to V DD.
8
Gain Error is a measure of the span error of the DAC.
9
In general terms, the bipolar input voltage range to the primary ADC is given by RangeADC = ± (VREF 2RN)/125, where:
VREF = REFIN(+) to REFIN(–) voltage and V REF = 1.25 V when internal ADC V REF is selected. RN = decimal equivalent of RN2, RN1, RN0, e.g., V REF = 2.5 V
and RN2, RN1, RN0 = 1, 1, 0 the Range ADC = ± 1.28 V. In unipolar mode, the effective range is 0 V to 1.28 V in our example.
10
1.25 V is used as the reference voltage to the ADC when internal V REF is selected via XREF0 and XREF1 bits in ADC0CON and ADC1CON, respectively.
11
In bipolar mode, the Auxiliary ADC can only be driven to a minimum of AGND – 30 mV as indicated by the Auxiliary ADC absolute AIN voltage limits. The
bipolar range is still –V REF to +VREF; however, the negative voltage is limited to –30 mV.
12
The ADuC834BCP (CSP Package) has been qualified and tested with the base of the CSP Package floating.
13
Pins configured in SPI Mode, pins configured as digital inputs during this test.
14
Pins configured in I 2C Mode only.
15
Flash/EE Memory Reliability Characteristics apply to both the Flash/EE program memory and Flash/EE data memory.
16
Endurance is qualified to 100 Kcycles as per JEDEC Std. 22 method A117 and measured at –40 °C, +25°C, +85°C, and +125°C. Typical endurance at 25°C
is 700 Kcycles.
17
Retention lifetime equivalent at junction temperature (T J) = 55°C as per JEDEC Std. 22, Method A117. Retention lifetime based on an activation energy of 0.6eV
will derate with junction temperature as shown in Figure 16 in the Flash/EE Memory section of this data sheet.
18
Power Supply current consumption is measured in Normal, Idle, and Power-Down modes under the following conditions:
Normal mode: Reset = 0.4 V, Digital I/O pins = open circuit, Core Clk changed via CD bits in PLLCON, Core Executing internal software loop.
Idle mode: Reset = 0.4 V, Digital I/O pins = open circuit, Core Clk changed via CD bits in PLLCON, PCON.0 = 1, Core Execution suspended in idle mode.
Power-Down mode: Reset = 0.4 V, All P0 pins and P1.2–P1.7 Pins = 0.4 V, All other digital I/O pins are open circuit, Core Clk changed via CD bits in
PLLCON, PCON.1 = 1, Core Execution suspended in power-down mode, OSC turned ON or OFF via OSC_PD bit (PLLCON.7) in PLLCON SFR.
19
DVDD power supply current will increase typically by 3 mA (3 V operation) and 10 mA (5 V operation) during a Flash/EE memory program or erase cycle.
Specifications subject to change without notice.
–8–
REV. A
ADuC834
ABSOLUTE MAXIMUM RATINGS1
PIN CONFIGURATION
52-Lead MQFP
(TA = 25°C, unless otherwise noted.)
AVDD to AGND . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to +7 V
AVDD to DGND . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to +7 V
DVDD to AGND . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to +7 V
DVDD to DGND . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to +7 V
AGND to DGND2 . . . . . . . . . . . . . . . . . . . . –0.3 V to +0.3 V
AVDD to DVDD . . . . . . . . . . . . . . . . . . . . . . . . . . –2 V to +5 V
Analog Input Voltage to AGND3 . . . . –0.3 V to AVDD + 0.3 V
Reference Input Voltage to AGND . . –0.3 V to AVDD + 0.3 V
AIN/REFIN Current (Indefinite) . . . . . . . . . . . . . . . . . 30 mA
Digital Input Voltage to DGND . . . . –0.3 V to DVDD + 0.3 V
Digital Output Voltage to DGND . . . –0.3 V to DVDD + 0.3 V
Operating Temperature Range . . . . . . . . . . –40°C to +125°C
Storage Temperature Range . . . . . . . . . . . . –65°C to +150°C
Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . 150°C
JA Thermal Impedance (MQFP) . . . . . . . . . . . . . . . . 90°C/W
JA Thermal Impedance (LFCSP Base Floating) . . . . . 52°C/W
Lead Temperature, Soldering
Vapor Phase (60 sec) . . . . . . . . . . . . . . . . . . . . . . . . . 215°C
Infrared (15 sec) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220°C
52
1
40
39
PIN 1
IDENTIFIER
ADuC834
TOP VIEW
(Not To Scale)
13
27
14
26
56-Lead LFCSP
56
PIN 1
IDENTIFIER
1
NOTES
1
Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the
device at these or any other conditions above those listed in the operational sections
of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
2
AGND and DGND are shorted internally on the ADuC834.
3
Applies to P1.2 to P1.7 pins operating in analog or digital input modes.
43
42
ADuC834
TOP VIEW
(Not To Scale)
14
29
15
28
ORDERING GUIDE
Model
ADuC834BS
ADuC834BCP
EVAL-ADuC834QS
Temperature
Range
Package
Description
Package
Option
–40°C to +125°C
–40°C to +85°C
52-Lead Metric Quad Flat Package
56-Lead Frame Chip Scale Package
QuickStart Development System
S-52
CP-56
CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily
accumulate on the human body and test equipment and can discharge without detection. Although the
ADuC834 features proprietary ESD protection circuitry, permanent damage may occur on devices
subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended
to avoid performance degradation or loss of functionality.
REV. A
–9–
37
38
39
ADuC834
BUF
AIN
MUX
ADC
CONTROL
AND
CALIBRATION
PRIMARY ADC
24-BIT
- ADC
AIN1
AIN2
DAC
CONTROL
PGA
AIN
MUX
AIN4
AIN5
TEMP
SENSOR
BAND GAP
REFERENCE
REFIN
ADC CONTROL
AND
CALIBRATION
19
MCU
CORE
PLL WITH PROG.
CLOCK DIVIDER
DGND
RESET
SINGLE-PIN
EMULATOR
40 42
26
27
14
13
32
33
XTAL1
DVDD
41
XTAL2
AGND
17
SS
AVDD
16
*PIN NUMBERS REFER TO THE 52-LEAD MQFP PACKAGE
SHADED AREAS REPRESENT THE NEW FEATURES OF THE ADuC834 OVER THE ADuC824
DAC
1
PWM0
2
PWM1
22
T0
23
T1
1
T2
2
T2EX
18
INT0
19
INT1
OSC
MISO
15
SPI/I2C SERIAL
INTERFACE
MOSI/SDATA
47 21 35
WAKE-UP/
RTC TIMER
UART
TIMER
3
POWER SUPPLY
MONITOR
SCLOCK
20 34 48
16-BIT
COUNTER
TIMERS
8052
EA
6
BUF
ALE
5
TXD
UART
SERIAL PORT
POR
25
PSEN
CURRENT
SOURCE
MUX
24
MUX
WATCHDOG
TIMER
200A
RXD
IEXC 1
23
DUAL
16-BIT
- DAC
DOWNLOADER
DEBUGGER
IEXC 2
22
12-BIT
VOLTAGE
OUTPUT DAC
2304 BYTES
USER RAM
4 KBYTES DATA
FLASH/EE
2 DATA POINTERS
11-BIT STACK POINTER
200A
18
DUAL
16-BIT
PWM
62 KBYTES PROGRAM/
FLASH/EE
VREF
DETECT
REFIN
17
PWM
CONTROL
AIN3
AUXILIARY ADC
16-BIT
- ADC
16
P3.6 (WR)
36
P3.7 (RD)
31
P3.4 (T0/PWMCLK)
30
P3.5 (T1)
29
P3.3 (INT1)
28
P3.2 (INT0)
12
P3.0 (RXD)
11
P3.1 (TXD)
10
P2.7 (A15/A23)
9
P2.6 (A14/A22)
4
P2.5 (A13/A21)
3
P2.3 (A11/A19)
2
P2.4 (A12/A20)
P1.3 (AIN5/IEXC 2)
1
P2.1 (A9/A17)
P1.2 (DAC/IEXC 1)
52
P2.2 (A10/A18)
P1.1 (T2EX)
51
P2.0 (A8/A16)
P1.0 (T2)
50
P1.7 (AIN4/DAC)
P0.7 (AD7)
49
P1.6 (AIN3)
P0.6 (AD6)
46
P1.4 (AIN1)
P0.5 (AD5)
45
P1.5 (AIN2)
P0.4 (AD4)
44
P0.2 (AD2)
43
P0.3 (AD3)
P0.0 (AD0)
P0.1 (AD1)
ADuC834
Figure 1. Detailed Block Diagram
PIN FUNCTION DESCRIPTIONS
Pin No. Pin No.
52-Lead 56-Lead
MQFP CSP
Mnemonic
Type* Description
1, 2
P1.0/P1.1
I/O
P1.0/T2/PWM0
I/O
56, 1
P1.1/T2EX/PWM1 I/O
P1.0 and P1.1 can function as a digital inputs or digital outputs and have a
pull-up configuration as described below for Port 3. P1.0 and P1.1 have an
increased current drive sink capability of 10 mA.
P1.0 and P1.1 also have various secondary functions as described below.
P1.0 can also be used to provide a clock input to Timer 2. When enabled, counter
2 is incremented in response to a negative transition on the T2 input pin.
If the PWM is enabled, the PWM0 output will appear at this pin.
P1.1 can also be used to provide a control input to Timer 2. When enabled, a
negative transition on the T2EX input pin will cause a Timer 2 capture or reload
event. If the PWM is enabled, the PWM1 output will appear at this pin.
–10–
REV. A
ADuC834
PIN FUNCTION DESCRIPTIONS (continued)
Pin No. Pin No.
52-Lead 56-Lead
MQFP CSP
Mnemonic
3–4,
9–12
2–3,
11–14
P1.2–P1.7
Type* Description
I
P1.2/DAC/IEXC1 I/O
P1.3/AIN5/IEXC2
P1.4/AIN1
P1.5/AIN2
P1.6/AIN3
P1.7/AIN4/DAC
I/O
I
I
I
I/O
Port 1.2 to Port 1.7 have no digital output driver; they can function as a digital
input for which ‘0’ must be written to the port bit. As a digital input, these pins
must be driven high or low externally.
These pins also have the following analog functionality:
The voltage output from the DAC or one or both current sources (200 A or
2 200 A) can be configured to appear at this pin.
Auxiliary ADC Input or one or both current sources can be configured at this pin.
Primary ADC, Positive Analog Input
Primary ADC, Negative Analog Input
Auxiliary ADC Input or Muxed Primary ADC, Positive Analog Input
Auxiliary ADC Input or Muxed Primary ADC, Negative Analog Input. The voltage
output from the DAC can also be configured to appear at this pin.
5
4, 5
AVDD
S
Analog Supply Voltage, 3 V or 5 V
6
6, 7, 8
AGND
S
Analog Ground. Ground reference pin for the analog circuitry.
7
9
REFIN(–)
I
Reference Input, Negative Terminal
8
10
REFIN(+)
I
Reference Input, Positive Terminal
13
15
SS
I
Slave Select Input for the SPI Interface. A weak pull-up is present on this pin.
14
16
MISO
I/O
Master Input/Slave Output for the SPI Interface. There is a weak pull-up on this
input pin.
15
17
RESET
I
Reset Input. A high level on this pin for 16 core clock cycles while the oscillator is
running resets the device. There is an internal weak pull-down and a Schmitt
trigger input stage on this pin.
16–19,
22–25
18–21,
24–27
P3.0–P3.7
I/O
P3.0/RXD
P3.1/TXD
P3.2/INT0
P3.3/INT1
P3.4/T0/
PWMCLK
P3.5/T1
P3.6/WR
I/O
I/O
I/O
I/O
I/O
P3.7/RD
I/O
Bidirectional port pins with internal pull-up resistors. Port 3 pins that have 1s written
to them are pulled high by the internal pull-up resistors, and in that state can be used
as inputs. As inputs, Port 3 pins being pulled externally low will source current
because of the internal pull-up resistors. When driving a 0-to-1 output transition,
a strong pull-up is active for two core clock periods of the instruction cycle.
Port 3 pins also have various secondary functions including:
Receiver Data for UART Serial Port
Transmitter Data for UART Serial Port
External Interrupt 0. This pin can also be used as a gate control input to Timer 0.
External Interrupt 1. This pin can also be used as a gate control input to Timer 1.
Timer/Counter 0 External Input. If the PWM is enabled, an external clock may be
input at this pin.
Timer/Counter 1 External Input
External Data Memory Write Strobe. Latches the data byte from Port 0 into an
external data memory.
External Data Memory Read Strobe. Enables the data from an external data
memory to Port 0.
I/O
I/O
20, 34, 48 22, 36, 51 DVDD
S
Digital Supply, 3 V or 5 V.
21, 35,
47
DGND
S
Digital Ground. Ground reference point for the digital circuitry.
26
SCLOCK
I/O
Serial Interface Clock for Either the I2C or SPI Interface. As an input, this pin is a
Schmitt-triggered input and a weak internal pull-up is present on this pin unless
it is outputting logic low. This pin can also be directly controlled in software as a
digital output pin.
27
MOSI/SDATA
I/O
Serial Data I/O for the I2C Interface or Master Output/Slave Input for the SPI
Interface. A weak internal pull-up is present on this pin unless it is outputting logic
low. This pin can also be directly controlled in software as a digital output pin.
REV. A
23, 37,
38, 50
–11–
ADuC834
PIN FUNCTION DESCRIPTIONS (continued)
Pin No. Pin No.
52-Lead 56-Lead
MQFP CSP
Mnemonic
Type* Description
28–31
36–39
30–33
39–42
P2.0–P2.7
(A8–A15)
(A16–A23)
I/O
Port 2 is a bidirectional port with internal pull-up resistors. Port 2 pins that have 1s
written to them are pulled high by the internal pull-up resistors, and in that state can
be used as inputs. As inputs, Port 2 pins being pulled externally low will source current
because of the internal pull-up resistors.
Port 2 emits the high order address bytes during fetches from external program memory
and middle and high order address bytes during accesses to the 24-bit external data
memory space.
32
34
XTAL1
I
Input to the Crystal Oscillator Inverter
33
35
XTAL2
O
Output from the Crystal Oscillator Inverter. (See “Hardware Design Considerations”
for description.)
40
43
EA
I/O
External Access Enable, Logic Input. When held high, this input enables the device
to fetch code from internal program memory locations 0000h to F7FFh. When held
low, this input enables the device to fetch all instructions from external program
memory. To determine the mode of code execution, i.e., internal or external, the
EA pin is sampled at the end of an external RESET assertion or as part of a device
power cycle. EA may also be used as an external emulation I/O pin, and therefore
the voltage level at this pin must not be changed during normal mode operation
as it may cause an emulation interrupt that will halt code execution.
41
44
PSEN
O
Program Store Enable, Logic Output. This output is a control signal that enables
the external program memory to the bus during external fetch operations. It is
active every six oscillator periods except during external data memory accesses.
This pin remains high during internal program execution.
PSEN can also be used to enable serial download mode when pulled low through a
resistor at the end of an external RESET assertion or as part of a device power cycle.
42
45
ALE
O
Address Latch Enable, Logic Output. This output is used to latch the low byte (and
page byte for 24-bit data address space accesses) of the address to external memory
during external code or data memory access cycles. It is activated every six oscillator
periods except during an external data memory access. It can be disabled by setting
the PCON.4 bit in the PCON SFR.
43–46
49–52
46–49
52–55
P0.0–P0.7
(AD0–AD3)
(AD4–AD7)
I/O
P0.0–P0.7, these pins are part of Port0, which is an 8-bit, open-drain, bidirectional
I/O port. Port 0 pins that have 1s written to them float and in that state can be used
as high impedance inputs. An external pull-up resistor will be required on P0 outputs
to force a valid logic high level externally. Port 0 is also the multiplexed low-order
address and databus during accesses to external program or data memory. In this
application, it uses strong internal pull-ups when emitting 1s.
*I = Input, O = Output, S = Supply.
–12–
REV. A
ADuC834
16 bytes (128 bits), locations 20H through 2FH above the register
banks, form a block of directly addressable bit locations at bit
addresses 00H through 7FH. The stack can be located anywhere
in the internal memory address space, and the stack depth can
be expanded up to 2048 bytes.
MEMORY ORGANIZATION
The ADuC834 contains four different memory blocks, namely:
• 62 Kbytes of On-Chip Flash/EE Program Memory
• 4 Kbytes of On-Chip Flash/EE Data Memory
• 256 bytes of General-Purpose RAM
Reset initializes the stack pointer to location 07H. Any CALL
or PUSH pre-increments the SP before loading the stack.
Therefore, loading the stack starts from locations 08H, which is
also the first register (R0) of register bank 1. Thus, if one is
going to use more than one register bank, the stack pointer should
be initialized to an area of RAM not used for data storage.
• 2 Kbytes of Internal XRAM
(1) Flash/EE Program Memory
The ADuC834 provides 62 Kbytes of Flash/EE program
memory to run user code. The user can choose to run code from
this internal memory or run code from an external program
memory.
If the user applies power or resets the device while the EA pin is
pulled low externally, the part will execute code from the external
program space; otherwise, if EA is pulled high externally, the
part defaults to code execution from its internal 62 Kbytes of
Flash/EE program memory.
Unlike the ADuC824, where code execution can overflow from
the internal code space to external code space once the PC
becomes greater than 1FFFH, the ADuC834 does not support
the rollover from F7FFH in internal code space to F800H in
external code space. Instead, the 2048 bytes between F800H
and FFFFH will appear as NOP instructions to user code.
7FH
GENERAL-PURPOSE
AREA
30H
2FH
BANKS
SELECTED
VIA
BITS IN PSW
BIT-ADDRESSABLE
(BIT ADDRESSES)
20H
1FH
11
18H
17H
10
10H
0FH
Permanently embedded firmware allows code to be serially
downloaded to the 62 Kbytes of internal code space via the
UART serial port while the device is in-circuit. No external
hardware is required.
FOUR BANKS OF EIGHT
REGISTERS
R0–R7
01
08H
07H
00
RESET VALUE OF
STACK POINTER
00H
56 Kbytes of the program memory can be reprogrammed during
runtime; thus the code space can be upgraded in the field using
a user defined protocol or it can be used as a data memory.
This will be discussed in more detail in the Flash/EE Memory
section of the data sheet.
Figure 2. Lower 128 Bytes of Internal Data Memory
(4) Internal XRAM
The ADuC834 contains 2 Kbytes of on-chip extended data
memory. This memory, although on-chip, is accessed via the
MOVX instruction. The 2 Kbytes of internal XRAM are
mapped into the bottom 2 Kbytes of the external address space
if the CFG834.0 bit is set. Otherwise, access to the external
data memory will occur just like a standard 8051.
(2) Flash/EE Data Memory
4 Kbytes of Flash/EE Data Memory are available to the user
and can be accessed indirectly via a group of registers mapped
into the Special Function Register (SFR) area. Access to the
Flash/EE Data memory is discussed in detail later as part of the
Flash/EE Memory section in this data sheet.
Even with the CFG834.0 bit set, access to the external XRAM
will occur once the 24-bit DPTR is greater than 0007FFH.
(3) General-Purpose RAM
FFFFFFH
FFFFFFH
The general-purpose RAM is divided into two separate memories,
namely the upper and the lower 128 bytes of RAM. The lower
128 bytes of RAM can be accessed through direct or indirect
addressing; the upper 128 bytes of RAM can only be accessed
through indirect addressing as it shares the same address space
as the SFR space, which can only be accessed through direct
addressing.
EXTERNAL
DATA
MEMORY
SPACE
(24-BIT
ADDRESS
SPACE)
The lower 128 bytes of internal data memory are mapped as
shown in Figure 2. The lowest 32 bytes are grouped into four
banks of eight registers addressed as R0 through R7. The next
EXTERNAL
DATA
MEMORY
SPACE
(24-BIT
ADDRESS
SPACE)
000800H
0007FFH
GENERAL NOTES PERTAINING TO THIS DATA SHEET
1. SET implies a Logic 1 state and CLEARED implies a Logic 0 state unless
otherwise stated.
2. SET and CLEARED also imply that the bit is set or automatically cleared by
the ADuC834 hardware unless otherwise stated.
3. User software should not write 1s to reserved or unimplemented bits as they may
be used in future products.
4. Any pin numbers used throughout this data sheet refer to the 52-lead MQFP
package, unless otherwise stated.
REV. A
000000H
000000H
CFG834.0 = 0
2 KBYTES
ON-CHIP
XRAM
CFG834.0 = 1
Figure 3. Internal and External XRAM
–13–
ADuC834
When accessing the internal XRAM, the P0 and P2 port pins,
as well as the RD and WR strobes, will not be output as per a
standard 8051 MOVX instruction. This allows the user to use
these port pins as standard I/O.
SPECIAL FUNCTION REGISTERS (SFRS)
The upper 1792 bytes of the internal XRAM can be configured
to be used as an extended 11-bit stack pointer. By default, the
stack will operate exactly like an 8052 in that it will roll over from
FFH to 00H in the general-purpose RAM. On the ADuC834
however, it is possible (by setting CFG834.7) to enable the 11-bit
extended stack pointer. In this case, the stack will roll over from
FFH in RAM to 0100H in XRAM. The 11-bit stack pointer is
visible in the SP and SPH SFRs. The SP SFR is located at 81H
as with a standard 8052. The SPH SFR is located at B7H. The
3 LSBs of this SFR contain the three extra bits necessary to extend
the 8-bit stack pointer into an 11-bit stack pointer.
The SFR space is mapped into the upper 128 bytes of internal
data memory space and accessed by direct addressing only. It
provides an interface between the CPU and all on-chip peripherals. A block diagram showing the programming model of the
ADuC834 via the SFR area is shown in Figure 5.
8051
COMPATIBLE
CORE
07FFH
256 BYTES RAM
2K XRAM
UPPER 1792
BYTES OF
ON-CHIP XRAM
(DATA + STACK
FOR EXSP = 1,
DATA ONLY
FOR EXSP = 0)
CFG834.7 = 0
CFG834.7 = 1
100H
00H
128-BYTE
SPECIAL
FUNCTION
REGISTER
AREA
DUAL - ADCs
OTHER ON-CHIP
PERIPHERALS
TEMP SENSOR
CURRENT SOURCES
12-BIT DAC
SERIAL I/O
WDT, PSM
TIC, PLL
Figure 5. Programming Model
All registers, except the Program Counter (PC) and the four
general-purpose register banks, reside in the SFR area. The SFR
registers include control, configuration, and data registers that
provide an interface between the CPU and all on-chip peripherals.
Accumulator SFR (ACC)
FFH
256 BYTES OF
ON-CHIP DATA
RAM
(DATA +
STACK)
4 KBYTE
ELECTRICALLY
REPROGRAMMABLE
NONVOLATILE
FLASH/EE DATA
MEMORY
62 KBYTE ELECTRICALLY
REPROGRAMMABLE
NONVOLATILE FLASH/EE
PROGRAM MEMORY
LOWER 256
BYTES OF
ON-CHIP XRAM
(DATA ONLY)
00H
Figure 4. Extended Stack Pointer Operation
External Data Memory (External XRAM)
Just like a standard 8051 compatible core, the ADuC834 can
access external data memory using a MOVX instruction. The
MOVX instruction automatically outputs the various control
strobes required to access the data memory.
The ADuC834 however, can access up to 16 Mbytes of external
data memory. This is an enhancement of the 64 Kbytes external
data memory space available on a standard 8051 compatible core.
The external data memory is discussed in more detail in the
ADuC834 Hardware Design Considerations section.
ACC is the Accumulator Register and is used for math operations
including addition, subtraction, integer multiplication and division,
and Boolean bit manipulations. The mnemonics for accumulatorspecific instructions refer to the Accumulator as A.
B SFR (B)
The B Register is used with the ACC for multiplication and
division operations. For other instructions, it can be treated as
a general-purpose scratchpad register.
Data Pointer (DPTR)
The Data Pointer is made up of three 8-bit registers, named DPP
(page byte), DPH (high byte) and DPL (low byte). These are
used to provide memory addresses for internal and external
code access and external data access. It may be manipulated as
a 16-bit register (DPTR = DPH, DPL), although INC DPTR
instructions will automatically carry over to DPP, or as three
independent 8-bit registers (DPP, DPH, DPL).
The ADuC834 supports dual data pointers. Refer to the Dual
Data Pointer section in this data sheet.
–14–
REV. A
ADuC834
Stack Pointer (SP and SPH)
Table II. PCON SFR Bit Designations
The SP SFR is the stack pointer and is used to hold an internal
RAM address that is called the ‘top of the stack.’ The SP Register
is incremented before data is stored during PUSH and CALL
executions. While the Stack may reside anywhere in on-chip
RAM, the SP Register is initialized to 07H after a reset. This
causes the stack to begin at location 08H.
As mentioned earlier, the ADuC834 offers an extended 11-bit
stack pointer. The three extra bits to make up the 11-bit stack
pointer are the 3 LSBs of the SPH byte located at B7H.
Program Status Word (PSW)
The PSW SFR contains several bits reflecting the current status
of the CPU as detailed in Table I.
SFR Address
Power-On Default Value
Bit Addressable
Description
7
6
5
4
3
CY
AC
F0
RS1
RS0
2
1
0
OV
F1
P
Carry Flag
Auxiliary Carry Flag
General-Purpose Flag
Register Bank Select Bits
RS1
RS0
Selected Bank
0
0
0
0
1
1
1
0
2
1
1
3
Overflow Flag
General-Purpose Flag
Parity Bit
Description
7
6
5
4
3
2
1
0
SMOD
SERIPD
INT0PD
ALEOFF
GF1
GF0
PD
IDL
Double UART Baud Rate
SPI Power-Down Interrupt Enable
INT0 Power-Down Interrupt Enable
Disable ALE Output
General-Purpose Flag Bit
General-Purpose Flag Bit
Power-Down Mode Enable
Idle Mode Enable
The CFG834 SFR contains the necessary bits to configure the
internal XRAM and the extended SP. By default it configures
the user into 8051 mode, i.e., extended SP is disabled, internal
XRAM is disabled.
SFR Address
Power-On Default Value
Bit Addressable
Table I. PSW SFR Bit Designations
Name
Name
ADuC834 CONFIGURATION SFR (CFG834)
D0H
00H
Yes
Bit
Bit
Table III. CFG834 SFR Bit Designations
Power Control SFR (PCON)
The PCON SFR contains bits for power-saving options and
general-purpose status flags as shown in Table II.
Bit
Name
Description
7
EXSP
6
5
4
3
2
1
0
–––
–––
–––
–––
–––
–––
XRAMEN
Extended SP Enable. If this bit is set, the
stack will roll over from SPH/SP = 00FFH
to 0100H. If this bit is clear, the SPH SFR
will be disabled and the stack will roll
over from SP = FFH to SP = 00H
Reserved for Future Use
Reserved for Future Use
Reserved for Future Use
Reserved for Future Use
Reserved for Future Use
Reserved for Future Use
XRAM Enable Bit. If this bit is set, the
internal XRAM will be mapped into the
lower 2 Kbytes of the external address
space. If this bit is clear, the internal
XRAM will not be accessible and the
external data memory will be mapped
into the lower 2 Kbytes of external data
memory. (See Figure 3.)
The TIC (wake-up/RTC timer) can be used to accurately wake up
the ADuC834 from power-down at regular intervals. To use the
TIC to wake up the ADuC834 from power-down, the OSC_PD
bit in the PLLCON SFR must be clear and the TIC must be
enabled.
SFR Address
Power-On Default Value
Bit Addressable
REV. A
AFH
00H
No
87H
00H
No
–15–
ADuC834
implemented; i.e., no register exists at this location. If an unoccupied location is read, an unspecified value is returned. SFR locations
that are reserved for future use are shaded (RESERVED) and
should not be accessed by user software.
COMPLETE SFR MAP
Figure 6 shows a full SFR memory map and the SFR contents
after RESET. NOT USED indicates unoccupied SFR locations. Unoccupied locations in the SFR address space are not
ISPI
WCOL
SPE
SPIM
CPOL
CPHA
SPR1
SPR0
FFH
0 FEH
0 FDH
0 FCH
0 FBH
0 FAH
1 F9H
0 F8H
0
F7H
0 F6H
0 F5H
0 F4H
0 F3H
0 F2H
0 F1H
0 F0H
0
DACL
SPICON
DACH
DACCON
RESERVED RESERVED
BITS
F8H
RESERVED RESERVED
FBH
04H
00H
FCH
00H
FDH
00H
B
MDO
MDE
MCO
I2CRS
I2CM
MDI
I2CTX
SPIDAT
RESERVED RESERVED
BITS
F0H
EFH
0 EEH
0 EDH
0 ECH
0 EBH
0 EAH
0 E9H
0 E8H
0
E7H
0
0 E5H
0 E4H
0 E3H
0 E2H
0 E1H
0 E0H
0
GN0L
0 D8H
0
RDY0
DFH
CY
D7H
TF2
CFH
PRE3
C7H
RDY1
0 DEH
AC
0 D6H
EXF2
0 CEH
PRE2
0 C6H
PADC
BFH
RD
B7H
EA
AFH
0 BEH
WR
1 B6H
EADC
0 AEH
CAL
0 DDH
NOXREF
0 DCH
F0
0 D5H
RSI
0 D4H
RCLK
0 CDH
TCLK
PRE0
0 C4H
PT2
0 BDH
PS
T1
1 B5H
PT1
0 BBH
INT1
T0
1 B4H
ET2
0 ADH
WDIR
1 C3H
0 BCH
1 B3H
ES
0 ACH
OV
ET1
0 ABH
FI
0 D2H
EXEN2
0 CBH
0 D9H
00H
0 D1H
TR2
CNT2
0 CAH
0 C9H
WDS
0 C2H
PX1
0 BAH
INT0
1 B2H
EX1
0 AAH
0 D0H
0
E9H
WDE
0 C1H
0
WDWR
0 C0H
PT0
0 B8H
00H
TXD
1 B1H
1 B0H
ET0
1
0 A9H
0 A8H
D8H
00H
0
SM0
1 A6H
SM1
1 A5H
1 A4H
SM2
1 A3H
REN
TB8
1 A2H
1 A1H
RB8
1 A0H
T1
9FH
0 9EH
0 9DH
0 9CH
0 9BH
0 9AH
0 99H
97H
1 96H
1 95H
1 94H
1 93H
1 92H
1 91H
TR1
TF0
TR0
IE1
IT1
00H
1
55H
OF0M
EBH
53H
OF0H
ECH
9AH
OF1L
EDH
59H
OF1H
E1H
00H
E2H
ADC0L
00H
ADC0M
E3H
80H
ADC0H
E4H
00H
ADC1L
E5H
80H
ADC1H
PSMCON
D9H
00H
DAH
00H
DBH
00H
ADCMODE
ADC0CON
ADC1CON
D1H
D2H
D3H
DCH
00H
SF
DDH
DFH
00H
ICON
DEH
PLLCON
00H
00H
07H
RCAP2L
00H
RCAP2H
D4H
45H
TL2
D5H
C8H
RESERVED RESERVED
CAH
00H
WDCON
BITS
00H
CBH
00H
CCH
00H
CDH
00H
EADRL
CHIPID
C2H
C6H
2H
ECON
BITS
EADRH
RESERVED RESERVED RESERVED
RESERVED
10H
C0H
03H
TH2
RESERVED
BITS
D7H
00H
EDATA1
EDATA2
00H
EDATA3
C7H
00H
EDATA4
RESERVED RESERVED
B8H
00H
B9H
BCH
00H
PWM0L
PWM0H
PWM1L
00H
FFH
00H
B1H
B2H
00H
B3H
00H
RESERVED RESERVED
00H
A9H
BEH
B4H
00H
RESERVED RESERVED
PWMCON
AEH
TIMECON
HTHSEC
SEC
2
MIN
2
HOUR
2
00H
INTVAL
BITS
A0H
FFH
A1H
00H
A2H
00H
A3H
00H
RESERVED RESERVED
98H
00H
A4H
00H
SBUF
BITS
99H
BFH
B7H
A0H
2
00H
00H
SPH
IEIP2
BITS
A8H
00H
RESERVED RESERVED
BITS
B0H
BDH
PWM1H
A5H
00H
T3FD
NOT USED
9DH
00H
00H
A6H
00H
T3CON
9EH
00H
CFG834
AFH
00H
DPCON
A7H
00H
RESERVED
00H
P1
T2
1 90H
IE0
0
GN1H
RESERVED
D0H
SCON
R1
0 98H
T2EX
TF1
1
1
BITS
P2
A7H
EAH
OF0L
IE
EX0
GN1L
RESERVED
P3
RXD
1
BITS
IP
0
GN0H
RESERVED RESERVED
E0H
0
PX0
B9H
55H
T2CON
CAP2
0 C8H
1
BITS
PSW
P
GN0M
RESERVED RESERVED
E8H
ADCSTAT
ERR1
0 DAH
RS0
0 D3H
0 CCH
PRE1
0 C5H
ERR0
0 DBH
1
BITS
ACC
E6H
RESERVED RESERVED RESERVED
F7H
I2CCON
I2CI
NOT USED
00H
1
RESERVED RESERVED
BITS
90H
TCON
IT0
8FH
0 8EH
0 8DH
0 8CH
0 8BH
0 8AH
0 89H
0 88H
0
87H
1 86H
1 85H
1 84H
1 83H
1 82H
1 81H
1 80H
1
RESERVED RESERVED RESERVED RESERVED RESERVED
FFH
TMOD
TL0
TL1
TH0
TH1
BITS
RESERVED RESERVED
88H
00H
89H
FFH
81H
P0
00H
8AH
07H
82H
SP
00H
DPL
8BH
00H
DPH
8CH
00H
8DH
00H
DPP
BITS
PCON
RESERVED RESERVED
80H
00H
83H
00H
84H
00H
87H
00H
NOTES
1CALIBRATION COEFFICIENTS ARE PRECONFIGURED AT POWER-UP TO FACTORY CALIBRATED VALUES.
2THESE SFRS MAINTAIN THEIR PRERESET VALUES AFTER A RESET IF TIMECON.0 = 1.
SFR MAP KEY:
THESE BITS ARE CONTAINED IN THIS BYTE.
BIT MNEMONIC
BIT BIT ADDRESS
RESET DEFAULT
BIT VALUE
IE0
89H
TCON
IT0
0 88H
0
88H
00H
MNEMONIC
RESET DEFAULT VALUE
SFR ADDRESS
SFR NOTE:
SFRs WHOSE ADDRESSES END IN 0H OR 8H ARE BIT-ADDRESSABLE.
Figure 6. Special Function Register Locations and Their Reset Default Values
–16–
REV. A
ADuC834
ADC SFR INTERFACE
Both ADCs are controlled and configured via a number of SFRs that are mentioned here and described in more detail in the
following pages.
ADCSTAT
ADC Status Register. Holds general status of
the primary and auxiliary ADCs.
ADC0L/M/H
Primary ADC 24-bit conversion result is held
in these three 8-bit registers.
ADCMODE
ADC Mode Register. Controls general modes
of operation for primary and auxiliary ADCs.
ADC1L/H
Auxiliary ADC 16-bit conversion result is held
in these two 8-bit registers.
ADC0CON
Primary ADC Control Register. Controls
specific configuration of primary ADC.
OF0L/M/H
Primary ADC 24-bit Offset Calibration
Coefficient is held in these three 8-bit registers.
ADC1CON
Auxiliary ADC Control Register. Controls
specific configuration of auxiliary ADC.
OF1L/H
Auxiliary ADC 16-bit Offset Calibration
Coefficient is held in these two 8-bit registers.
SF
Sinc Filter Register. Configures the decimation
factor for the Sinc3 filter and thus the primary
and auxiliary ADC update rates.
GN0L/M/H
Primary ADC 24-bit Gain Calibration
Coefficient is held in these three 8-bit registers.
GN1L/H
ICON
Current Source Control Register. Allows
user control of the various on-chip current
source options.
Auxiliary ADC 16-bit Gain Calibration
Coefficient is held in these two 8-bit registers.
ADCSTAT—(ADC Status Register)
This SFR reflects the status of both ADCs including data ready, calibration, and various (ADC-related) error and warning conditions
including reference detect and conversion overflow/underflow flags.
SFR Address
Power-On Default Value
Bit Addressable
D8H
00H
Yes
Table IV. ADCSTAT SFR Bit Designations
Bit
Name
Description
7
RDY0
Ready Bit for primary ADC.
Set by hardware on completion of ADC conversion or calibration cycle.
Cleared directly by the user or indirectly by write to the mode bits to start another primary
ADC conversion or calibration. The primary ADC is inhibited from writing further results to its
data or calibration registers until the RDY0 bit is cleared.
6
RDY1
Ready Bit for auxiliary ADC. Same definition as RDY0 referred to the auxiliary ADC.
5
CAL
Calibration Status Bit.
Set by hardware on completion of calibration.
Cleared indirectly by a write to the mode bits to start another ADC conversion or calibration.
4
NOXREF
No External Reference Bit (only active if primary or auxiliary ADC is active).
Set to indicate that one or both of the REFIN pins is floating or the applied voltage is below
a specified threshold. When Set, conversion results are clamped to all ones, if using external
reference.
Cleared to indicate valid VREF.
3
ERR0
Primary ADC Error Bit.
Set by hardware to indicate that the result written to the primary ADC data registers has
been clamped to all zeros or all ones. After a calibration, this bit also flags error conditions that
caused the calibration registers not to be written.
Cleared by a write to the mode bits to initiate a conversion or calibration.
2
ERR1
Auxiliary ADC Error Bit. Same definition as ERR0 referred to the auxiliary ADC.
1
–––
Reserved for Future Use
0
–––
Reserved for Future Use
REV. A
–17–
ADuC834
ADCMODE (ADC Mode Register)
Used to control the operational mode of both ADCs.
SFR Address
Power-On Default Value
Bit Addressable
D1H
00H
No
Table V. ADCMODE SFR Bit Designations
Bit
Name
Description
7
–––
Reserved for Future Use
6
–––
Reserved for Future Use
5
ADC0EN
Primary ADC Enable.
Set by the user to enable the primary ADC and place it in the mode selected in MD2–MD0 below.
Cleared by the user to place the primary ADC in power-down mode.
4
ADC1EN
Auxiliary ADC Enable.
Set by the user to enable the auxiliary ADC and place it in the mode selected in MD2–MD0 below.
Cleared by the user to place the auxiliary ADC in power-down mode.
3
–––
Reserved for Future Use
2
MD2
Primary and auxiliary ADC Mode bits.
1
MD1
These bits select the operational mode of the enabled ADC as follows:
0
MD0
MD2 MD1 MD0
0
0
0
ADC Power-Down Mode (Power-On Default)
0
0
1
Idle Mode. In Idle Mode, the ADC filter and modulator are held in a reset state
although the modulator clocks are still provided.
0
1
0
Single Conversion Mode. In Single Conversion Mode, a single conversion is
performed on the enabled ADC. On completion of the conversion, the ADC data
registers (ADC0H/M/L and/or ADC1H/L) are updated, the relevant flags in the
ADCSTAT SFR are written, and power-down is re-entered with the MD2–MD0
accordingly being written to 000.
0
1
1
Continuous Conversion. In Continuous Conversion Mode, the ADC data registers
are regularly updated at the selected update rate (see SF Register).
1
0
0
Internal Zero-Scale Calibration. Internal short automatically connected to the
enabled ADC input(s).
1
0
1
Internal Full-Scale Calibration Internal or External VREF (as determined by
XREF0 and XREF1 bits in ADC0/1CON) is automatically connected to the
enabled ADC input(s) for this calibration.
1
1
0
System Zero-Scale Calibration. User should connect system zero-scale input to
the enabled ADC input(s) as selected by CH1/CH0 and ACH1/ACH0 bits in
the ADC0/1CON Register.
1
1
1
System Full-Scale Calibration. User should connect system full-scale input to
the enabled ADC input(s) as selected by CH1/CH0 and ACH1/ACH0 bits in the
ADC0/1CON Register.
NOTES
1. Any change to the MD bits will immediately reset both ADCs. A write to the MD2–0 Bits with no change is also treated as a reset. (See exception to this in Note 3 below.)
2. If ADC0CON is written when ADC0EN = 1, or if ADC0EN is changed from 0 to 1, then both ADCs are also immediately reset. In other words, the primary ADC
is given priority over the auxiliary ADC and any change requested on the primary ADC is immediately responded to.
3. On the other hand, if ADC1CON is written or if ADC1EN is changed from 0 to 1, only the auxiliary ADC is reset. For example, if the primary ADC is continuously
converting when the auxiliary ADC change or enable occurs, the primary ADC continues undisturbed. Rather than allow the auxiliary ADC to operate with a phase
difference from the primary ADC, the auxiliary ADC will fall into step with the outputs of the primary ADC. The result is that the first conversion time for the
auxiliary ADC will be delayed up to three outputs while the auxiliary ADC update rate is synchronized to the primary ADC.
4. Once ADCMODE has been written with a calibration mode, the RDY0/1 bits (ADCSTAT) are immediately reset and the calibration commences. On completion,
the appropriate calibration registers are written, the relevant bits in ADCSTAT are written, and the MD2–0 bits are reset to 000 to indicate the ADC is back in
power-down mode.
5. Any calibration request of the auxiliary ADC while the temperature sensor is selected will fail to complete. Although the RDY1 bit will be set at the end of the
calibration cycle, no update of the calibration SFRs will take place and the ERR1 bit will be set.
6. Calibrations are performed at maximum SF (see SF SFR) value guaranteeing optimum calibration operation.
–18–
REV. A
ADuC834
ADC0CON (Primary ADC Control Register) and ADC1CON (Auxiliary ADC Control Register)
The ADC0CON and ADC1CON SFRs are used to configure the primary and auxiliary ADC for reference and channel selection,
unipolar or bipolar coding and, in the case of the primary ADC, for range (the auxiliary ADC operates on a fixed input range of ± VREF).
ADC0CON
SFR Address
Power-On Default Value
Bit Addressable
Primary ADC Control SFR
D2H
07H
No
ADC1CON
SFR Address
Power-On Default Value
Bit Addressable
Auxiliary ADC Control SFR
D3H
00H
No
Table VI. ADC0CON SFR Bit Designations
Bit
Name
Description
7
6
–––
XREF0
5
4
CH1
CH0
3
UNI0
2
1
0
RN2
RN1
RN0
Reserved for Future Use
Primary ADC External Reference Select Bit.
Set by user to enable the primary ADC to use the external reference via REFIN(+)/REFIN(–).
Cleared by user to enable the primary ADC to use the internal band gap reference (VREF = 1.25 V).
Primary ADC Channel Selection Bits
Written by the user to select the differential input pairs used by the primary ADC as follows:
CH1
CH0
Positive Input
Negative Input
0
0
AIN1
AIN2
0
1
AIN3
AIN4
1
0
AIN2
AIN2 (Internal Short)
1
1
AIN3
AIN2
Primary ADC Unipolar Bit.
Set by user to enable unipolar coding, i.e., zero differential input will result in 000000H output.
Cleared by user to enable bipolar coding, i.e., zero differential input will result in 800000H output.
Primary ADC Range Bits.
Written by the user to select the primary ADC input range as follows:
RN2
RN1
RN0 Selected Primary ADC Input Range (VREF = 2.5 V)
0
0
0
± 20 mV (0 mV–20 mV in Unipolar Mode)
0
0
1
± 40 mV (0 mV–40 mV in Unipolar Mode)
0
1
0
± 80 mV (0 mV–80 mV in Unipolar Mode)
0
1
1
± 160 mV
(0 mV–160 mV in Unipolar Mode)
1
0
0
± 320 mV
(0 mV–320 mV in Unipolar Mode)
1
0
1
± 640 mV
(0 mV–640 mV in Unipolar Mode)
1
1
0
± 1.28 V (0 V–1.28 V in Unipolar Mode)
1
1
1
± 2.56 V (0 V–2.56 V in Unipolar Mode)
Table VII. ADC1CON SFR Bit Designations
Bit
Name
Description
7
6
–––
XREF1
5
4
ACH1
ACH0
3
UNI1
2
1
0
–––
–––
–––
Reserved for Future Use
Auxiliary ADC External Reference Bit.
Set by user to enable the auxiliary ADC to use the external reference via REFIN(+)/REFIN(–).
Cleared by user to enable the auxiliary ADC to use the internal band gap reference.
Auxiliary ADC Channel Selection Bits.
Written by the user to select the single-ended input pins used to drive the auxiliary ADC as follows:
ACH1
ACH0
Positive Input
Negative Input
0
0
AIN3
AGND
0
1
AIN4
AGND
1
0
Temp Sensor
AGND (Temp Sensor routed to the ADC input)
1
1
AIN5
AGND
Auxiliary ADC Unipolar Bit.
Set by user to enable unipolar coding, i.e., zero input will result in 0000H output.
Cleared by user to enable bipolar coding, i.e., zero input will result in 8000H output.
Reserved for Future Use
Reserved for Future Use
Reserved for Future Use
NOTES
1. When the temperature sensor is selected, user code must select internal reference via XREF1 bit above and clear the UNI1 bit (ADC1CON.3) to select bipolar coding.
2. The temperature sensor is factory calibrated to yield conversion results 8000H at 0 °C.
3. A +1°C change in temperature will result in a +1 LSB change in the ADC1H Register ADC conversion result.
REV. A
–19–
ADuC834
ADC0H/ADC0M/ADC0L (Primary ADC Conversion Result Registers)
These three 8-bit registers hold the 24-bit conversion result from the primary ADC.
SFR Address
Power-On Default Value
Bit Addressable
ADC0H
ADC0M
ADC0L
00H
No
High Data Byte
DBH
Middle Data Byte
DAH
Low Data Byte
D9H
ADC0H, ADC0M, ADC0L
ADC0H, ADC0M, ADC0L
ADC1H/ADC1L (Auxiliary ADC Conversion Result Registers)
These two 8-bit registers hold the 16-bit conversion result from the auxiliary ADC.
SFR Address
Power-On Default Value
Bit Addressable
ADC1H
ADC1L
00H
No
High Data Byte
Low Data Byte
ADC1H, ADC1L
ADC1H, ADC1L
DDH
DCH
OF0H/OF0M/OF0L (Primary ADC Offset Calibration Registers*)
These three 8-bit registers hold the 24-bit offset calibration coefficient for the primary ADC. These registers are configured at power-on
with a factory default value of 800000H. However, these bytes will be automatically overwritten if an internal or system zero-scale
calibration of the primary ADC is initiated by the user via MD2–0 bits in the ADCMODE Register.
SFR Address
Power-On Default Value
Bit Addressable
OF0H
OF0M
OF0L
800000H
No
Primary ADC Offset Coefficient High Byte
Primary ADC Offset Coefficient Middle Byte
Primary ADC Offset Coefficient Low Byte
OF0H, OF0M, OF0L, respectively
OF0H, OF0M, OF0L
E3H
E2H
E1H
OF1H/OF1L (Auxiliary ADC Offset Calibration Registers*)
These two 8-bit registers hold the 16-bit offset calibration coefficient for the auxiliary ADC. These registers are configured at power-on
with a factory default value of 8000H. However, these bytes will be automatically overwritten if an internal or system zero-scale calibration of the auxiliary ADC is initiated by the user via the MD2–0 bits in the ADCMODE Register.
SFR Address
Power-On Default Value
Bit Addressable
OF1H
OF1L
8000H
No
Auxiliary ADC Offset Coefficient High Byte
Auxiliary ADC Offset Coefficient Low Byte
OF1H and OF1L, respectively
OF1H, OF1L
E5H
E4H
GN0H/GN0M/GN0L (Primary ADC Gain Calibration Registers*)
These three 8-bit registers hold the 24-bit gain calibration coefficient for the primary ADC. These registers are configured at power-on
with a factory-calculated internal full-scale calibration coefficient. Every device will have an individual coefficient. However, these
bytes will be automatically overwritten if an internal or system full-scale calibration of the primary ADC is initiated by the user via
MD2–0 bits in the ADCMODE Register.
SFR Address
GN0H
Primary ADC Gain Coefficient High Byte
EBH
GN0M
Primary ADC Gain Coefficient Middle Byte
EAH
GN0L
Primary ADC Gain Coefficient Low Byte
E9H
Power-On Default Value
Configured at Factory Final Test; see Notes above.
Bit Addressable
No
GN0H, GN0M, GN0L
GN1H/GN1L (Auxiliary ADC Gain Calibration Registers*)
These two 8-bit registers hold the 16-bit gain calibration coefficient for the auxiliary ADC. These registers are configured at power-on
with a factory-calculated internal full-scale calibration coefficient. Every device will have an individual coefficient. However, these
bytes will be automatically overwritten if an internal or system full-scale calibration of the auxiliary ADC is initiated by the user via
MD2–0 bits in the ADCMODE Register.
SFR Address
Power-On Default Value
Bit Addressable
GN1H
GN1L
No
Auxiliary ADC Gain Coefficient High Byte
Auxiliary ADC Gain Coefficient Low Byte
Configured at Factory Final Test; see Notes above.
GN1H, GN1L
EDH
ECH
*These registers can be overwritten by user software only if Mode bits MD0–2 (ADCMODE SFR) are zero.
–20–
REV. A
ADuC834
SF (Sinc Filter Register)
The number in this register sets the decimation factor and thus
the output update rate for the primary and auxiliary ADCs.
This SFR cannot be written by user software while either ADC
is active. The update rate applies to both primary and auxiliary
ADCs and is calculated as follows:
f ADC =
Where:
1
1
×
× f MOD
3 8 × SF
value for the SF Register is 45H, resulting in a default ADC
update rate of just under 20 Hz. Both ADC inputs are chopped
to minimize offset errors, which means that the settling time for
a single conversion, or the time to a first conversion result in
Continuous Conversion mode, is 2 tADC. As mentioned earlier,
all calibration cycles will be carried out automatically with a
maximum, i.e., FFH, SF value to ensure optimum calibration
performance. Once a calibration cycle has completed, the value
in the SF Register will be that programmed by user software.
fADC = ADC Output Update Rate
Table VIII. SF SFR Bit Designations
fMOD = Modulator Clock Frequency = 32.768 kHz
SF = Decimal Value of SF Register
The allowable range for SF is 0DH to FFH. Examples of SF values
and corresponding conversion update rates (fADC) and conversion
times (tADC) are shown in Table VIII. The power-on default
SF(dec)
SF(hex)
fADC(Hz)
tADC(ms)
13
69
255
0D
45
FF
105.3
19.79
5.35
9.52
50.34
186.77
ICON (Current Sources Control Register)
Used to control and configure the various excitation and burnout current source options available on-chip.
SFR Address
Power-On Default Value
Bit Addressable
D5H
00H
No
Table IX. ICON SFR Bit Designations
Bit
Name
Description
7
–––
Reserved for Future Use
6
BO
Burnout Current Enable Bit.
Set by user to enable both transducer burnout current sources in the primary ADC signal paths.
Cleared by user to disable both transducer burnout current sources.
5
ADC1IC
Auxiliary ADC Current Correction Bit.
Set by user to allow scaling of the auxiliary ADC by an internal current source calibration word.
4
ADC0IC
Primary ADC Current Correction Bit.
Set by user to allow scaling of the primary ADC by an internal current source calibration word.
3
I2PIN*
Current Source-2 Pin Select Bit.
Set by user to enable current source-2 (200 A) to external Pin 3 (P1.2/DAC/IEXC1).
Cleared by user to enable current source-2 (200 A) to external Pin 4 (P1.3/AIN5/IEXC2).
2
I1PIN*
Current Source-1 Pin Select Bit.
Set by user to enable current source-1 (200 A) to external Pin 4 (P1.3/AIN5/IEXC2).
Cleared by user to enable current source-1 (200 A) to external Pin 3 (P1.2/DAC/IEXC1).
1
I2EN
Current Source-2 Enable Bit.
Set by user to turn on excitation current source-2 (200 A).
Cleared by user to turn off excitation current source-2 (200 A).
0
I1EN
Current Source-1 Enable Bit.
Set by user to turn on excitation current source-1 (200 A).
Cleared by user to turn off excitation current source-1 (200 A).
*Both current sources can be enabled to the same external pin, yielding a 400 A current source.
REV. A
–21–
ADuC834
selected via the Sinc Filter (SF) SFR. It is important to note
that the peak-to-peak resolution figures represent the resolution
for which there will be no code flicker within a six-sigma limit.
The QuickStart Development system PC software comes
complete with an ADC noise evaluation tool. This tool can be
easily used with the evaluation board to see these figures from
silicon.
PRIMARY AND AUXILIARY ADC NOISE
PERFORMANCE
Tables X, XI, and XII show the output rms noise in V and
output peak-to-peak resolution in bits (rounded to the nearest
0.5 LSB) for some typical output update rates on both the primary
and auxiliary ADCs. The numbers are typical and are generated
at a differential input voltage of 0 V. The output update rate is
Table X. Primary ADC, Typical Output RMS Noise (V)
Typical Output RMS Noise vs. Input Range and Update Rate; Output RMS Noise in V
SF
Word
Data Update
Rate (Hz)
20 mV
40 mV
80 mV
Input Range
160 mV
320 mV
640 mV
1.28 V
2.56 V
13
69
255
105.3
19.79
5.35
1.50
0.60
0.35
1.50
0.65
0.35
1.60
0.65
0.37
1.75
0.65
0.37
3.50
0.65
0.37
4.50
0.95
0.51
6.70
1.40
0.82
11.75
2.30
1.25
Table XI. Primary ADC, Peak-to-Peak Resolution (Bits)
Peak-to-Peak Resolution vs. Input Range and Update Rate; Peak-to-Peak Resolution in Bits
SF
Word
Data Update
Rate (Hz)
20 mV
40 mV
80 mV
Input Range
160 mV
320 mV
640 mV
1.28 V
2.56 V
13
69
255
105.3
19.79
5.35
12
13.5
14
13
14
15
14
15
16
15
16
17
15
17
18
15.5
17.5
18.5
16
18
19
16
18.5
19.5
Typical RMS Resolution vs. Input Range and Update Rate: RMS Resolution in Bits*
SF
Word
Data Update
Rate (Hz)
20 mV
40 mV
80 mV
Input Range
160 mV
320 mV
640 mV
1.28 V
2.56 V
13
69
255
105.3
19.79
5.35
14.7
16.2
16.7
15.7
16.7
17.7
16.7
17.7
18.7
17.7
18.7
19.7
17.7
19.7
20.7
18.2
20.2
21.2
18.7
20.7
21.7
18.7
21.2
22.2
*Based on a six-sigma limit, the rms resolution is 2.7 bits greater than the peak-to-peak resolution.
Table XII. Auxiliary ADC
Peak-to-Peak Resolution vs. Update Rate 1
Peak-to-Peak Resolution in Bits
Typical Output RMS Noise vs. Update Rate*
Output RMS Noise in V
SF
Data Update
Rate (Hz)
Input Range
Word
2.5 V
SF
Word
Data Update
Rate (Hz)
Input Range
2.5 V
13
69
255
105.3
19.79
5.35
10.75
2.00
1.15
13
69
255
105.3
19.79
5.35
162
16
16
*ADC converting in Bipolar mode
NOTES
1
ADC converting in Bipolar mode
2
In Unipolar mode, peak-to-peak resolution at 105 Hz is 15 bits.
–22–
REV. A
ADuC834
PRIMARY AND AUXILIARY ADC CIRCUIT DESCRIPTION
Overview
The ADuC834 incorporates two independent - ADCs (primary
and auxiliary) with on-chip digital filtering intended for the measurement of wide dynamic range, low frequency signals such as those
in weigh-scale, strain gage, pressure transducer, or temperature
measurement applications.
Primary ADC
This ADC is intended to convert the primary sensor input. The
input is buffered and can be programmed for one of eight input
ranges from ± 20 mV to ± 2.56 V being driven from one of three
differential input channel options AIN1/2, AIN3/4, or AIN3/2.
The input channel is internally buffered, allowing the part to
handle significant source impedances on the analog input and
PROGRAMMABLE GAIN
AMPLIFIER
ANALOG INPUT CHOPPING
BURNOUT CURRENTS
TWO 100nA BURNOUT
CURRENTS ALLOW THE
USER TO EASILY DETECT
IF A TRANSDUCER HAS
BURNED OUT OR GONE
OPEN-CIRCUIT.
THE PROGRAMMABLE
GAIN AMPLIFIER ALLOWS
EIGHT UNIPOLAR AND
EIGHT BIPOLAR INPUT
RANGES FROM 20mV TO
2.56V (EXT V REF = 2.5V).
THE INPUTS ARE
ALTERNATELY REVERSED
THROUGH THE
CONVERSION CYCLE.
CHOPPING YIELDS
EXCELLENT ADC OFFSET
AND OFFSET DRIFT
PERFORMANCE.
allowing R/C filtering (for noise rejection or RFI reduction) to be
placed on the analog inputs if required. On-chip burnout currents
can also be turned on. These currents can be used to check that
a transducer on the selected channel is still operational before
attempting to take measurements.
The ADC employs a - conversion technique to realize up to
24 bits of no missing codes performance. The - modulator converts the sampled input signal into a digital pulse train whose duty
cycle contains the digital information. A Sinc3 programmable lowpass filter is then employed to decimate the modulator output data
stream to give a valid data conversion result at programmable
output rates from 5.35 Hz (186.77 ms) to 105.03 Hz (9.52 ms).
A chopping scheme is also employed to minimize ADC offset errors.
A block diagram of the primary ADC is shown in Figure 7.
DIFFERENTIAL
REFERENCE
THE EXTERNAL REFERENCE
INPUT TO THE ADuC834 IS
DIFFERENTIAL AND
FACILITATES RATIOMETRIC
OPERATION. THE EXTERNAL
REFERENCE VOLTAGE IS
SELECTED VIA THE XREF0 BIT
IN ADC0CON.
REFERENCE DETECT
CIRCUITRY TESTS FOR OPEN OR
SHORTED REFERENCE INPUTS.
- ADC
OUTPUT AVERAGE
THE - ARCHITECTURE
ENSURES 24 BITS NO
MISSING CODES. THE
ENTIRE - ADC IS
CHOPPED TO REMOVE
DRIFT ERROR.
AS PART OF THE CHOPPING
IMPLEMENTATION, EACH
DATA-WORD OUTPUT
FROM THE FILTER IS
SUMMED AND AVERAGED
WITH ITS PREDECESSOR
TO NULL ADC CHANNEL
OFFSET ERRORS.
REFIN(–) REFIN(+)
AVDD
AIN1
AIN2
DIGTAL OUTPUT
RESULT WRITTEN
TO ADC0H/M/L
SFRS
- ADC
BUFFER
MUX
PGA
-
MODULATOR
PROGRAMMABLE
DIGITAL
FILTER
OUTPUT
AVERAGE
OUTPUT
SCALING
AIN3
CHOP
AIN4
CHOP
AGND
OUTPUT SCALING
ANALOG MULTIPLEXER
A DIFFERENTIAL MULTIPLEXER
ALLOWS SELECTION OF THREE
FULLY DIFFERENTIAL PAIR OPTIONS AND
ADDITIONAL INTERNAL SHORT OPTION
(AIN2–AIN2). THE MULTIPLEXER IS
CONTROLLED VIA THE CHANNEL
SELECTION BITS IN ADC0CON.
BUFFER AMPLIFIER
THE BUFFER AMPLIFIER
PRESENTS A HIGH
IMPEDANCE INPUT STAGE
FOR THE ANALOG INPUTS,
ALLOWING SIGNIFICANT
EXTERNAL SOURCE
IMPEDANCES.
- MODULATOR
PROGRAMMABLE
DIGITAL FILTER
THE MODULATOR PROVIDES
A HIGH FREQUENCY 1-BIT
DATA STREAM (THE OUTPUT
OF WHICH IS ALSO CHOPPED)
TO THE DIGITAL FILTER,
THE DUTY CYCLE OF WHICH
REPRESENTS THE SAMPLED
ANALOG INPUT VOLTAGE.
THE SINC3 FILTER REMOVES
QUANTIZATION NOISE INTRODUCED
BY THE MODULATOR. THE UPDATE
RATE AND BANDWIDTH OF THIS
FILTER ARE PROGRAMMABLE
VIA THE SF SFR.
Figure 7. Primary ADC Block Diagram
REV. A
–23–
THE OUPUT WORD FROM THE
DIGITAL FILTER IS SCALED
BY THE CALIBRATION
COEFFICIENTS BEFORE
BEING PROVIDED AS
THE CONVERSION RESULT.
ADuC834
Auxiliary ADC
The auxiliary ADC is intended to convert supplementary inputs
such as those from a cold junction diode or thermistor. This ADC
is not buffered and has a fixed input range of 0 V to 2.5 V
(assuming an external 2.5 V reference). The single-ended inputs
can be driven from AIN3, AIN4, or AIN5 Pins, or directly from
the on-chip temperature sensor voltage. A block diagram of the
auxiliary ADC is shown in Figure 8.
Analog Input Channels
The primary ADC has four associated analog input pins (labelled
AIN1 to AIN4) that can be configured as two fully differential input
channels. Channel selection bits in the ADC0CON SFR detailed
in Table VI allow three combinations of differential pair selection
as well as an additional shorted input option (AIN2–AIN2).
The auxiliary ADC has three external input pins (labelled AIN3 to
AIN5) as well as an internal connection to the on-chip temperature
sensor. All inputs to the auxiliary ADC are single-ended inputs
referenced to the AGND on the part. Channel selection bits in
the ADC1CON SFR previously detailed in Table VII allow
selection of one of four inputs.
Two input multiplexers switch the selected input channel to the
on-chip buffer amplifier in the case of the primary ADC and
directly to the - modulator input in the case of the auxiliary
ADC. When the analog input channel is switched, the settling
time of the part must elapse before a new valid word is available
from the ADC.
DIFFERENTIAL REFERENCE
ANALOG INPUT CHOPPING
THE INPUTS ARE ALTERNATELY
REVERSED THROUGH THE
CONVERSION CYCLE. CHOPPING
YIELDS EXCELLENT ADC
OFFSET AND OFFSET DRIFT
PERFORMANCE.
THE EXTERNAL REFERENCE INPUT
TO THE ADuC834 IS DIFFERENTIAL
AND FACILITATES RATIOMETRIC
OPERATION. THE EXTERNAL
REFERENCE VOLTAGE IS SELECTED
VIA THE XREF1 BIT IN ADC1CON.
REFERENCE DETECT
CIRCUITRY TESTS FOR OPEN OR
SHORTED REFERENCE INPUTS.
- ADC
OUTPUT AVERAGE
THE - ARCHITECTURE
ENSURES 16 BITS NO MISSING
CODES. THE ENTIRE - ADC
IS CHOPPED TO REMOVE
DRIFT ERRORS.
AS PART OF THE CHOPPING
IMPLEMENTATION, EACH
DATA-WORD OUTPUT
FROM THE FILTER IS
SUMMED AND AVERAGED
WITH ITS PREDECESSOR
TO NULL ADC CHANNEL
OFFSET ERRORS.
REFIN(–) REFIN(+)
- ADC
AIN3
-
MODULATOR
AIN4
MU
AIN5
ON-CHIP
TEMPERATURE
SENSOR
PROGRAMMABLE
DIGITAL FILTER
OUTPUT
AVERAGE
OUTPUT
SCALING
DIGTAL OUTPUT
RESULT WRITTEN
TO ADC1H/L SFRs
MUX
X
CHOP
CHOP
OUTPUT SCALING
ANALOG MULTIPLEXER
A DIFFERENTIAL MULTIPLEXER
ALLOWS SELECTION OF THREE
EXTERNAL SINGLE ENDED INPUTS
OR THE ON-CHIP TEMP. SENSOR.
THE MULTIPLEXER IS CONTROLLED
VIA THE CHANNEL SELECTION
BITS IN ADC1CON.
PROGRAMMABLE DIGITAL
FILTER
- MODULATOR
THE SINC3 FILTER REMOVES
QUANTIZATION NOISE INTRODUCED
BY THE MODULATOR. THE UPDATE
RATE AND BANDWIDTH OF THIS
FILTER ARE PROGRAMMABLE
VIA THE SF SFR.
THE MODULATOR PROVIDES A
HIGH FREQUENCY 1-BIT DATA
STREAM (THE OUTPUT OF WHICH
IS ALSO CHOPPED) TO THE
DIGITAL FILTER,
THE DUTY CYCLE OF WHICH
REPRESENTS THE SAMPLED
ANALOG INPUT VOLTAGE.
THE OUPUT WORD FROM THE
DIGITAL FILTER IS SCALED BY
THE CALIBRATION
COEFFICIENTS BEFORE
BEING PROVIDED AS
THE CONVERSION RESULT.
Figure 8. Auxiliary ADC Block Diagram
–24–
REV. A
ADuC834
19.372
Primary and Auxiliary ADC Inputs
The output of the primary ADC multiplexer feeds into a high
impedance input stage of the buffer amplifier. As a result, the primary ADC inputs can handle significant source impedances and
are tailored for direct connection to external resistive-type sensors
like strain gages or Resistance Temperature Detectors (RTDs).
ADC INPUT VOLTAGE – mV
19.371
The auxiliary ADC, however, is unbuffered, resulting in higher
analog input current on the auxiliary ADC. It should be noted
that this unbuffered input path provides a dynamic load to the
driving source. Therefore, resistor/capacitor combinations on
the input pins can cause dc gain errors depending on the output
impedance of the source that is driving the ADC inputs.
19.369
19.368
19.367
19.366
19.365
Analog Input Ranges
19.364
The absolute input voltage range on the auxiliary ADC is restricted
to between AGND – 30 mV to AVDD + 30 mV. The slightly
negative absolute input voltage limit does allow the possibility
of monitoring small signal bipolar signals using the single-ended
auxiliary ADC front end.
Programmable Gain Amplifier
The output from the buffer on the primary ADC is applied to the
input of the on-chip programmable gain amplifier (PGA). The
PGA can be programmed through eight different unipolar input
ranges and bipolar ranges. The PGA gain range is programmed
via the range bits in the ADC0CON SFR. With the external
reference select bit set in the ADC0CON SFR and an external
2.5 V reference, the unipolar ranges are 0 mV to 20 mV, 0 mV to
40 mV, 0 mV to 80 mV, 0 mV to 160 mV, 0 mV to 320 mV, 0 mV
to 640 mV, 0 V to 1.28 V, and 0 to 2.56 V; the bipolar ranges are
± 20 mV, ± 40 mV, ± 80 mV, ± 160 mV, ± 320 mV, ± 640 mV,
± 1.28 V, and ± 2.56 V. These are the nominal ranges that should
appear at the input to the on-chip PGA. An ADC range matching specification of 2 V (typ) across all ranges means that
calibration need only be carried out at a single gain range and
does not have to be repeated when the PGA gain range is changed.
Typical matching across ranges is shown in Figure 9. Here, the
primary ADC is configured in bipolar mode with an external
2.5 V reference, while just greater than 19 mV is forced on its
inputs. The ADC continuously converts the dc input voltage at
an update rate of 5.35 Hz, i.e., SF = FFH. In total, 800 conversion results are gathered. The first 100 results are gathered with
the primary ADC operating in the ± 20 mV range. The ADC
range is then switched to ± 40 mV, 100 more conversion results
are gathered, and so on until the last group of 100 samples is
gathered with the ADC configured in the ± 2.56 V range. From
Figure 9, the variation in the sample mean through each range,
i.e., the range matching, is seen to be of the order of 2 V.
600
700
800
2.56V
500
1.28V
400
640mV
300
320mV
200
160mV
20mV
ADC RANGE
100
80mV
SAMPLE COUNT 0
40mV
The absolute input voltage range on the primary ADC is restricted
to between AGND + 100 mV to AVDD – 100 mV. Care must be
taken in setting up the common-mode voltage and input voltage
range so that these limits are not exceeded; otherwise there will
be a degradation in linearity performance.
Figure 9. Primary ADC Range Matching
Bipolar/Unipolar Inputs
The analog inputs on the ADuC834 can accept either unipolar or
bipolar input voltage ranges. Bipolar input ranges do not imply that
the part can handle negative voltages with respect to system AGND.
Unipolar and bipolar signals on the AIN(+) input on the primary
ADC are referenced to the voltage on the respective AIN(–)
input. For example, if AIN(–) is 2.5 V and the primary ADC is
configured for an analog input range of 0 mV to 20 mV, the input
voltage range on the AIN(+) input is 2.5 V to 2.52 V. If AIN(–)
is 2.5 V and the ADuC834 is configured for an analog input
range of 1.28 V, the analog input range on the AIN(+) input is
1.22 V to 3.78 V (i.e., 2.5 V ± 1.28 V).
As mentioned earlier, the auxiliary ADC input is a single-ended
input with respect to the system AGND. In this context, a bipolar
signal on the auxiliary ADC can only span 30 mV negative with
respect to AGND before violating the voltage input limits for
this ADC.
Bipolar or unipolar options are chosen by programming the
primary and auxiliary Unipolar enable bits in the ADC0CON
and ADC1CON SFRs respectively. This programs the relevant
ADC for either unipolar or bipolar operation. Programming for
either unipolar or bipolar operation does not change any of the
input signal conditioning; it simply changes the data output coding
and the points on the transfer function where calibrations occur.
When an ADC is configured for unipolar operation, the output
coding is natural (straight) binary with a zero differential input
voltage resulting in a code of 000 . . . 000, a midscale voltage
resulting in a code of 100 . . . 000, and a full-scale input voltage
resulting in a code of 111 . . . 111. When an ADC is configured
for bipolar operation, the coding is offset binary with a negative
full-scale voltage resulting in a code of 000 . . . 000, a zero
differential voltage resulting in a code of 100 . . . 000, and a
positive full-scale voltage resulting in a code of 111 . . . 111.
The auxiliary ADC does not incorporate a PGA and is configured
for a fixed single input range of 0 to VREF.
REV. A
19.370
–25–
ADuC834
If the voltage measured is 0 V, it indicates that the transducer
has short circuited. For normal operation, these burnout currents
are turned off by writing a 0 to the BO bit in the ICON SFR.
The current sources work over the normal absolute input voltage
range specifications.
Reference Input
The ADuC834’s reference inputs, REFIN(+) and REFIN(–),
provide a differential reference input capability. The commonmode range for these differential inputs is from AGND to AVDD.
The nominal reference voltage, VREF (REFIN(+) – REFIN(–)),
for specified operation is 2.5 V with the primary and auxiliary
reference enable bits set in the respective ADC0CON and/or
ADC1CON SFRs.
Excitation Currents
The part is also functional (although not specified for performance)
when the XREF0 or XREF1 bits are 0, which enables the on-chip
internal band gap reference. In this mode, the ADCs will see the
internal reference of 1.25 V, therefore halving all input ranges.
As a result of using the internal reference voltage, a noticeable
degradation in peak-to-peak resolution will result. Therefore,
for best performance, operation with an external reference is
strongly recommended.
In applications where the excitation (voltage or current) for the
transducer on the analog input also drives the reference voltage
for the part, the effect of the low frequency noise in the excitation
source will be removed as the application is ratiometric. If the
ADuC834 is not used in a ratiometric application, a low noise
reference should be used. Recommended reference voltage sources
for the ADuC834 include the AD780, REF43, and REF192.
It should also be noted that the reference inputs provide a high
impedance, dynamic load. Because the input impedance of each
reference input is dynamic, resistor/capacitor combinations on
these inputs can cause dc gain errors depending on the output
impedance of the source that is driving the reference inputs.
Reference voltage sources, like those recommended above
(e.g., AD780), will typically have low output impedances and
therefore decoupling capacitors on the REFIN(+) input would
be recommended. Deriving the reference input voltage across an
external resistor, as shown in Figure 66, will mean that the reference input sees a significant external source impedance. External
decoupling on the REFIN(+) and REFIN(–) pins would not be
recommended in this type of circuit configuration.
Burnout Currents
The primary ADC on the ADuC834 contains two 100 nA constant
current generators, one sourcing current from AVDD to AIN(+),
and one sinking from AIN(–) to AGND. The currents are switched
to the selected analog input pair. Both currents are either on or
off, depending on the Burnout Current Enable (BO) bit in the
ICON SFR (see Table IX). These currents can be used to verify
that an external transducer is still operational before attempting
to take measurements on that channel. Once the burnout currents are turned on, they will flow in the external transducer
circuit, and a measurement of the input voltage on the analog
input channel can be taken. If the resultant voltage measured is
full-scale, it indicates that the transducer has gone open-circuit.
The ADuC834 also contains two identical, 200 A constant
current sources. Both source current from AVDD to Pin 3 (IEXC1)
or Pin 4 (IEXC2). These current sources are controlled via bits
in the ICON SFR shown in Table IX. They can be configured
to source 200 A individually to both pins or a combination of
both currents, i.e., 400 A, to either of the selected pins. These
current sources can be used to excite external resistive bridge or
RTD sensors.
Reference Detect
The ADuC834 includes on-chip circuitry to detect if the part has
a valid reference for conversions or calibrations. If the voltage
between the external REFIN(+) and REFIN(–) pins goes below
0.3 V or either the REFIN(+) or REFIN(–) inputs is open circuit,
the ADuC834 detects that it no longer has a valid reference. In
this case, the NOXREF bit of the ADCSTAT SFR is set to a 1.
If the ADuC834 is performing normal conversions and the
NOXREF bit becomes active, the conversion results revert to all
1s. It is not necessary to continuously monitor the status of the
NOXREF bit when performing conversions. It is only necessary
to verify its status if the conversion result read from the ADC
Data Register is all 1s.
If the ADuC834 is performing either an offset or gain calibration
and the NOXREF bit becomes active, the updating of the respective calibration registers is inhibited to avoid loading incorrect
coefficients to these registers, and the appropriate ERR0 or
ERR1 bits in the ADCSTAT SFR are set. If the user is concerned
about verifying that a valid reference is in place every time a
calibration is performed, the status of the ERR0 or ERR1 bit
should be checked at the end of the calibration cycle.
- Modulator
A - ADC generally consists of two main blocks, an analog
modulator and a digital filter. In the case of the ADuC834
ADCs, the analog modulators consist of a difference amplifier,
an integrator block, a comparator, and a feedback DAC as
illustrated in Figure 10.
ANALOG
INPUT
DIFFERENCE
AMP
COMPARATOR
INTEGRATOR
HIGH
FREQUENCY
BITSTREAM
TO DIGITAL
FILTER
DAC
Figure 10. - Modulator Simplified Block Diagram
–26–
REV. A
ADuC834
The response of the filter, however, will change with SF word as
can be seen in Figure 12, which shows >90 dB NMR at 50 Hz
and >70 dB NMR at 60 Hz when SF = 255 dec.
0
–10
–20
–30
–40
GAIN – dB
In operation, the analog signal sample is fed to the difference
amplifier along with the output of the feedback DAC. The
difference between these two signals is integrated and fed to the
comparator. The output of the comparator provides the input to
the feedback DAC so the system functions as a negative feedback
loop that tries to minimize the difference signal. The digital
data that represents the analog input voltage is contained in the
duty cycle of the pulse train appearing at the output of the comparator. This duty cycle data can be recovered as a data-word
using a subsequent digital filter stage. The sampling frequency of
the modulator loop is many times higher than the bandwidth
of the input signal. The integrator in the modulator shapes the
quantization noise (which results from the analog-to-digital
conversion) so that the noise is pushed toward one-half of the
modulator frequency.
–60
–70
–80
–90
–100
Digital Filter
The output of the - modulator feeds directly into the digital
filter. The digital filter then band-limits the response to a frequency significantly lower than one-half of the modulator frequency.
In this manner, the 1-bit output of the comparator is translated
into a band-limited, low noise output from the ADuC834 ADCs.
The ADuC834 filter is a low-pass, Sinc3 or (SIN x/x)3 filter
whose primary function is to remove the quantization noise
introduced at the modulator. The cutoff frequency and decimated
output data rate of the filter are programmable via the SF (Sinc
Filter) SFR as described in Table VIII.
–110
–120
0
30
50
40
60
FREQUENCY – Hz
70
80
90
110
Figure 12. Filter Response, SF = 255 dec
0
–10
–20
–30
It should also be noted that rejection of mains-related frequency
components, i.e., 50 Hz and 60 Hz, is seen to be at a level of
>65 dB at 50 Hz and >100 dB at 60 Hz. This confirms the data
sheet specifications for 50 Hz/60 Hz Normal Mode Rejection
(NMR) at a 20 Hz update rate.
GAIN – dB
–40
It should be noted that this frequency response allows frequency
components higher than the ADC Nyquist frequency to pass
through the ADC, in some cases without significant attenuation.
These components may, therefore, be aliased and appear
in-band after the sampling process.
–50
–60
–70
–80
–90
–100
–110
–120
10
0
–10
–20
–20
–30
–30
–40
–40
GAIN – dB
0
–50
–60
–70
30
50
70
90
110 130 150 170 190 210 230 250
SF – Decimal
Figure 13. 50 Hz Normal Mode Rejection vs. SF
–10
–50
–60
–70
–80
–80
–90
–90
–100
–100
–110
–110
–120
10
–120
0
10
20
30
50
70
40
60
FREQUENCY – Hz
80
90
100
110
30
50
70
90
110 130 150 170 190 210 230 250
SF – Decimal
Figure 14. 60 Hz Normal Mode Rejection vs. SF
Figure 11. Filter Response, SF = 69 dec
REV. A
20
10
Figures 13 and 14 show the NMR for 50 Hz and 60 Hz across
the full range of SF word, i.e., SF = 13 dec to SF = 255 dec.
Figure 11 shows the frequency response of the ADC channel at
the default SF word of 69 dec or 45H, yielding an overall output
update rate of just under 20 Hz.
GAIN – dB
–50
–27–
ADuC834
ADC Chopping
input voltages provided to the input of the modulator during
calibration. The result of the zero-scale calibration conversion is
stored in the Offset Calibration Registers for the appropriate
ADC. The result of the full-scale calibration conversion is stored
in the Gain Calibration Registers for the appropriate ADC.
With these readings, the calibration logic can calculate the offset
and the gain slope for the input-to-output transfer function of
the converter.
Both ADCs on the ADuC834 implement a chopping scheme
whereby the ADC repeatedly reverses its inputs. The decimated
digital output words from the Sinc3 filters therefore have a
positive offset and negative offset term included.
As a result, a final summing stage is included in each ADC so
that each output word from the filter is summed and averaged
with the previous filter output to produce a new valid output
result to be written to the ADC data SFRs. In this way, while
the ADC throughput or update rate is as discussed earlier and
illustrated in Table VIII, the full settling time through the ADC
(or the time to a first conversion result), will actually be given
by 2 tADC.
During an internal zero-scale or full-scale calibration, the respective
zero-scale input and full-scale input are automatically connected
to the ADC input pins internally to the device. A system calibration, however, expects the system zero-scale and system full-scale
voltages to be applied to the external ADC pins before the calibration mode is initiated. In this way, external ADC errors are
taken into account and minimized as a result of system calibration.
It should also be noted that to optimize calibration accuracy, all
ADuC834 ADC calibrations are carried out automatically at the
slowest update rate.
The chopping scheme incorporated in the ADuC834 ADC
results in excellent dc offset and offset drift specifications and is
extremely beneficial in applications where drift, noise rejection,
and optimum EMI rejection are important factors.
Calibration
The ADuC834 provides four calibration modes that can be
programmed via the mode bits in the ADCMODE SFR detailed
in Table V. In fact, every ADuC834 has already been factory
calibrated. The resultant Offset and Gain calibration coefficients for both the primary and auxiliary ADCs are stored
on-chip in manufacturing-specific Flash/EE memory locations.
At power-on or after reset, these factory calibration coefficients
are automatically downloaded to the calibration registers in the
ADuC834 SFR space. Each ADC (primary and auxiliary) has
dedicated calibration SFRs, these have been described earlier as
part of the general ADC SFR description. However, the factory
calibration values in the ADC calibration SFRs will be overwritten if any one of the four calibration options are initiated and
that ADC is enabled via the ADC enable bits in ADCMODE.
Even though an internal offset calibration mode is described
below, it should be recognized that both ADCs are chopped.
This chopping scheme inherently minimizes offset and means
that an internal offset calibration should never be required. Also,
because factory 5 V/25°C gain calibration coefficients are automatically present at power-on, an internal full-scale calibration
will only be required if the part is being operated at 3 V or at
temperatures significantly different from 25°C.
The ADuC834 offers internal or system calibration facilities. For
full calibration to occur on the selected ADC, the calibration
logic must record the modulator output for two different input
conditions. These are zero-scale and full-scale points. These
points are derived by performing a conversion on the different
Internally in the ADuC834, the coefficients are normalized
before being used to scale the words coming out of the digital
filter. The offset calibration coefficient is subtracted from the
result prior to the multiplication by the gain coefficient.
From an operational point of view, a calibration should be
treated like another ADC conversion. A zero-scale calibration
(if required) should always be carried out before a full-scale
calibration. System software should monitor the relevant ADC
RDY0/1 bit in the ADCSTAT SFR to determine end of calibration via a polling sequence or interrupt driven routine.
NONVOLATILE FLASH/EE MEMORY
Flash/EE Memory Overview
The ADuC834 incorporates Flash/EE memory technology on-chip
to provide the user with nonvolatile, in-circuit reprogrammable,
code and data memory space. Flash/EE memory is a relatively
recent type of nonvolatile memory technology and is based on a
single transistor cell architecture. This technology is basically an
outgrowth of EPROM technology and was developed through
the late 1980s. Flash/EE memory takes the flexible in-circuit
reprogrammable features of EEPROM and combines them with
the space efficient/density features of EPROM. (See Figure 15).
Because Flash/EE technology is based on a single transistor cell
architecture, a Flash memory array, like EPROM, can be implemented to achieve the space efficiencies or memory densities
required by a given design.
–28–
REV. A
ADuC834
Like EEPROM, Flash memory can be programmed in-system at
a byte level, although it must first be erased; the erase being
performed in page blocks. Thus, Flash memory is often and
more correctly referred to as Flash/EE memory.
EPROM
TECHNOLOGY
As indicated in the specification pages of this data sheet, the
ADuC834 Flash/EE memory endurance qualification has been
carried out in accordance with JEDEC Specification A117 over
the industrial temperature range of –40°C, +25°C, +85°C, and
+125°C. The results allow the specification of a minimum
endurance figure over supply and temperature of 100,000
cycles, with an endurance figure of 700,000 cycles being typical
of operation at 25°C.
EEPROM
TECHNOLOGY
SPACE EFFICIENT/
DENSITY
In reliability qualification, every byte in both the program and
data Flash/EE memory is cycled from 00H to FFH until a first
fail is recorded, signifying the endurance limit of the on-chip
Flash/EE memory.
IN-CIRCUIT
REPROGRAMMABLE
FLASH/EE MEMORY
TECHNOLOGY
Retention quantifies the ability of the Flash/EE memory to retain
its programmed data over time. Again, the ADuC834 has been
qualified in accordance with the formal JEDEC Retention Lifetime Specification (A117) at a specific junction temperature
(T J = 55°C). As part of this qualification procedure, the
Flash/EE memory is cycled to its specified endurance limit
described above, before data retention is characterized. This
means that the Flash/EE memory is guaranteed to retain its data
for its full specified retention lifetime every time the Flash/EE
memory is reprogrammed. It should also be noted that retention
lifetime, based on an activation energy of 0.6 eV, will derate
with TJ as shown in Figure 16.
Figure 15. Flash/EE Memory Development
Overall, Flash/EE memory represents a step closer to the ideal
memory device that includes nonvolatility, in-circuit programmability, high density, and low cost. Incorporated in the
ADuC834, Flash/EE memory technology allows the user to
update program code space in-circuit, without the need to replace
onetime programmable (OTP) devices at remote operating nodes.
Flash/EE Memory and the ADuC834
The ADuC834 provides two arrays of Flash/EE memory for
user applications. 62 Kbytes of Flash/EE Program space are
provided on-chip to facilitate code execution without any external discrete ROM device requirements. The program memory
can be programmed in-circuit, using the serial download mode
provided, using conventional third party memory programmers,
or via any user defined protocol in User Download (ULOAD) Mode.
300
250
RETENTION – Years
A 4 Kbyte Flash/EE Data Memory space is also provided on-chip.
This may be used as a general-purpose, nonvolatile scratchpad
area. User access to this area is via a group of seven SFRs. This
space can be programmed at a byte level, although it must first
be erased in 4-byte pages.
ADuC834 Flash/EE Memory Reliability
The Flash/EE Program and Data Memory arrays on the ADuC834
are fully qualified for two key Flash/EE memory characteristics,
namely Flash/EE Memory Cycling Endurance and Flash/EE
Memory Data Retention.
Endurance quantifies the ability of the Flash/EE memory to be
cycled through many Program, Read, and Erase cycles. In real
terms, a single endurance cycle is composed of four independent,
sequential events. These events are defined as:
c. byte program sequence
A single Flash/EE
Memory Endurance
Cycle
d. second read/verify sequence
REV. A
ADI SPECIFICATION
100 YEARS MIN.
AT TJ = 55C
150
100
50
0
40
50
80
60
70
90
TJ JUNCTION TEMPERATURE – C
100
110
Figure 16. Flash/EE Memory Data Retention
a. initial page erase sequence
b. read/verify sequence
200
–29–
ADuC834
Flash/EE Program Memory
(2) Parallel Programming
The ADuC834 contains a 64 Kbyte array of Flash/EE program
memory. The lower 62 Kbytes of this program memory is available to the user, and can be used for program storage or indeed
as additional NV data memory.
The parallel programming mode is fully compatible with conventional third party Flash or EEPROM device programmers. A block
diagram of the external pin configuration required to support parallel
programming is shown in Figure 18. In this mode, Ports 0, and 2
operate as the external address bus interface, P3 operates as the
external data bus interface and P1.0 operates as the Write Enable
strobe. Port 1.1, P1.2, P1.3, and P1.4 are used as a general
configuration port that configures the device for various program
and erase operations during parallel programming.
The upper 2 Kbytes of this Flash/EE program memory array
contain permanently embedded firmware, allowing in circuit serial
download, serial debug and nonintrusive single pin emulation.
These 2 Kbytes of embedded firmware also contain a power-on
configuration routine that downloads factory calibrated coefficients to the various calibrated peripherals (ADC, temperature
sensor, current sources, bandgap references and so on).
Table XIII. Flash/EE Memory Parallel Programming Modes
This 2 Kbyte embedded firmware is hidden from user code.
Attempts to read this space will read 0s, i.e., the embedded firmware
appears as NOP instructions to user code.
In normal operating mode (power up default) the 62 Kbytes of
user Flash/EE program memory appear as a single block. This
block is used to store the user code as shown in Figure 17.
EMBEDDED DOWNLOAD/DEBUG KERNEL
PERMANENTLY EMBEDDED FIRMWARE ALLOWS CODE
TO BE DOWNLOADED TO ANY OF THE 62 KBYTES OF
ON-CHIP PROGRAM MEMORY. THE KERNEL PROGRAM
APPEARS AS ‘NOP’ INSTRUCTIONS TO USER CODE.
FFFFH
2 KBYTE
F800H
USER PROGRAM MEMORY
62 KBYTES OF FLASH/EE PROGRAM MEMORY IS
AVAILABLE TO THE USER. ALL OF THIS SPACE CAN
BE PROGRAMMED FROM THE PERMANENTLY
EMBEDDED DOWNLOAD/DEBUG KERNEL OR IN
PARALLEL PROGRAMMING MODE.
62 KBYTE
F7FFH
P1.4
Port 1 Pins
P1.3 P1.2
P1.1
Programming Mode
0
0
0
0
1
0
0
1
0
1
0
0
1
1
0
1
0
0
1
1
1
0
1
1
0
All other codes
1
0
0
1
1
0
1
Erase Flash/EE Program,
Data, and Security Modes
Read Device Signature/ID
Program Code Byte
Program Data Byte
Read Code Byte
Read Data Byte
Program Security Modes
Read/Verify Security Modes
Redundant
5V
VDD
ADuC834
P3
GND
PROGRAM MODE
(SEE TABLE XIII)
P1.1 -> P1.4
P0
0000H
COMMAND
ENABLE
Figure 17. Flash/EE Program Memory Map in
Normal Mode
In Normal Mode, the 62 Kbytes of Flash/EE program memory
can be programmed programmed in two ways, namely:
ENTRY
SEQUENCE
P1.0
GND
EA
GND
PSEN
VDD
P2
P1.5 -> P1.7
PROGRAM
DATA
(D0–D7)
PROGRAM
ADDRESS
(A0–A13)
(P2.0 = A0)
(P1.7 = A13)
TIMING
RESET
(1) Serial Downloading (In-Circuit Programming)
The ADuC834 facilitates code download via the standard UART
serial port. The ADuC834 will enter Serial Download mode
after a reset or power cycle if the PSEN pin is pulled low through
an external 1 kΩ resistor. Once in serial download mode, the
hidden embedded download kernel will execute. This allows the
user to download code to the full 62 Kbytes of Flash/EE program
memory while the device is in circuit in its target application
hardware.
A PC serial download executable is provided as part of the
ADuC834 QuickStart development system. Appliction Note
uC004 fully describes the serial download protocol that is used
by the embedded download kernel. This Appliction Note is
available at www.analog.com/microconverter.
Figure 18. Flash/EE Memory Parallel Programming
User Download Mode (ULOAD)
In Figure 17 we can see that it was possible to use the 62 Kbytes
of Flash/EE program memory available to the user as one single
block of memory. In this mode all of the Flash/EE memory is
read only to user code.
However, the Flash/EE program memory can also be written to
during runtime simply by entering ULOAD mode. In ULOAD
mode, the lower 56 Kbytes of program memory can be erased
and reprogrammed by user software as shown in Figure 19.
ULOAD mode can be used to upgrade your code in the field via
any user defined download protocol. Configuring the SPI port on
the ADuC834 as a slave, it is possible to completely reprogram
the 56 Kbytes of Flash/EE program memory in only 5 seconds.
See Application Note uC007.
–30–
REV. A
ADuC834
Alternatively ULOAD Mode can be used to save data to the
56 Kbytes of Flash/EE memory. This can be extremely useful in
datalogging applications where the ADuC834 can provide up to
60 Kbytes of NV data memory on-chip (4 Kbytes of dedicated
Flash/EE data memory also exist).
The upper 6 Kbytes of the 62 Kbytes of Flash/EE program
memory is only programmable via serial download or parallel
programming. This means that this space appears as read only
to user code. Therefore, it cannot be accidently erased or reprogrammed by erroneous code execution. This makes it very
suitable to use the 6 Kbytes as a bootloader. A Bootload Enable
option exists in the serial downloader to “Always RUN from
E000h after Reset.” If using a bootloader, this option is recommended to ensure that the bootloader always executes correct
code after reset.
Programming the Flash/EE program memory via ULOAD
mode is described in more detail in the description of ECON
and also in Application Note uC007.
EMBEDDED DOWNLOAD/DEBUG KERNEL
PERMANENTLY EMBEDDED FIRMWARE ALLOWS CODE
TO BE DOWNLOADED TO ANY OF THE 62 KBYTES OF
ON-CHIP PROGRAM MEMORY. THE KERNEL PROGRAM
APPEARS AS ‘NOP’ INSTRUCTIONS TO USER CODE.
62 KBYTES
OF USER
CODE
MEMORY
USER BOOTLOADER SPACE
THE USER BOOTLOADER SPACE
CAN BE PROGRAMMED IN
DOWNLOAD/DEBUG MODE VIA THE
KERNEL BUT IS READ ONLY WHEN
EXECUTING USER CODE
USER DOWNLOAD SPACE
EITHER THE DOWNLOAD/DEBUG KERNEL
OR USER CODE (IN ULOAD MODE) CAN
PROGRAM THIS SPACE.
FFFFH
2 KBYTE
F800H
F7FFH
6 KBYTE
E000H
DFFFH
56 KBYTE
Flash/EE Program Memory Security
The ADuC834 facilitates three modes of Flash/EE program
memory security. These modes can be independently activated,
restricting access to the internal code space. These security
modes can be enabled as part of serial download protocol, as
described in Application Note uC004, or via parallel programming. The ADuC834 offers the following security modes:
Lock Mode
This mode locks the code memory, disabling parallel programming of the program memory. However, reading the memory in
Parallel Mode and reading the memory via a MOVC command
from external memory are still allowed. This mode is deactivated
by initiating an “erase code and data” command in Serial Download or Parallel Programming modes.
Secure Mode
This mode locks the code memory, disabling parallel programming of the program memory. Reading/Verifying the memory in
Parallel Mode and reading the internal memory via a MOVC
command from external memory is also disabled. This mode is
deactivated by initiating an “erase code and data” command in
Serial Download or Parallel Programming Modes.
Serial Safe Mode
This mode disables serial download capability on the device. If
Serial Safe mode is activated and an attempt is made to reset
the part into Serial Download mode, i.e., RESET asserted and
deasserted with PSEN low, the part will interpret the serial
download reset as a normal reset only. It will therefore not enter
Serial Download mode, but only execute a normal reset sequence.
Serial Safe mode can only be disabled by initiating an “erase
code and data” command in parallel programming mode.
0000H
Figure 19. Flash/EE Program Memory Map in
ULOAD Mode
REV. A
–31–
3FFH
BYTE 1
(0FFCH)
BYTE 2
(0FFDH)
BYTE 3
(0FFEH)
BYTE 4
(0FFFH)
3FEH
BYTE 1
(0FF8H)
BYTE 2
(0FF9H)
BYTE 3
(0FFAH)
BYTE 4
(0FFBH)
03H
BYTE 1
(000CH)
BYTE 2
(000DH)
BYTE 3
(000EH)
BYTE 4
(000FH)
02H
BYTE 1
(0008H)
BYTE 2
(0009H)
BYTE 3
(000AH)
BYTE 4
(000BH)
01H
BYTE 1
(0004H)
BYTE 2
(0005H)
BYTE 3
(0006H)
BYTE 4
(0007H)
BYTE 1
(0000H)
BYTE 2
(0001H)
BYTE 3
(0002H)
BYTE 4
(0003H)
EDATA3 SFR
EDATA4 SFR
PAGE ADDRESS
(EADRH/L)
The 4 Kbytes of Flash/EE data memory is configured as 1024 pages,
each of 4 bytes. As with the other ADuC834 peripherals, the
interface to this memory space is via a group of registers mapped
in the SFR space. A group of four data registers (EDATA1–4)
is used to hold the 4 bytes of data at each page. The page is
addressed via the two registers EADRH and EADRL. Finally,
ECON is an 8-bit control register that may be written with one
of nine Flash/EE memory access commands to trigger various
read, write, erase, and verify functions.
EDATA2 SFR
Using the Flash/EE Data Memory
EDATA1 SFR
ADuC834
00H
A block diagram of the SFR interface to the Flash/EE data
memory array is shown in Figure 20.
ECON—Flash/EE Memory Control SFR
BYTE
ADDRESSES
ARE GIVEN IN
BRACKETS
Programming of either the Flash/EE data memory or the Flash/EE
program memory is done through the Flash/EE Memory Control
SFR (ECON). This SFR allows the user to read, write, erase or
verify the 4 Kbytes of Flash/EE data memory or the 56 Kbytes
of Flash/EE program memory.
Figure 20. Flash/EE Data Memory Control and Configuration
Table XIV. ECON—Flash/EE Memory Commands
Command Description
(Normal Mode) (Power-On Default)
Command Description
(ULOAD Mode)
Not Implemented. Use the MOVC instruction.
02H
WRITE
Results in 4 bytes in the Flash/EE data memory,
addressed by the page address EADRH/L,
being read into EDATA 1 to 4.
Results in 4 bytes in EDATA1–4 being written to the
Flash/EE data memory, at the page address given by
EADRH. (0 ≤ EADRH < 0400H)
Note: The 4 bytes in the page being addressed must
be pre-erased.
Results in bytes 0–255 of internal XRAM being written
to the 256 bytes of Flash/EE program memory at the page
address given by EADRH/L (0 ≤ EADRH/L < E0H)
Note: The 256 bytes in the page being addressed must
be pre-erased.
03H
Reserved Command
Reserved Command
04H
VERIFY
Verifies if the data in EDATA1–4 is contained in the
page address given by EADRH/L. A subsequent read
of the ECON SFR will result in a 0 being read if the
verification is valid, or a nonzero value being read to
indicate an invalid verification.
Not Implemented. Use the MOVC and MOVX instructions
to verify the WRITE in software.
05H
ERASE PAGE
Results in the erase of the 4 bytes page of Flash/EE data
memory addressed by the page address EADRH/L
Results in the 64-bytes page of Flash/EE program memory,
addressed by the byte address EADRH/L being erased.
EADRL can equal any of 64 locations within the page. A new
page starts whenever EADRL is equal to 00H, 40H, 80H, or C0H
06H
ERASE ALL
Results in the erase of entire 4 Kbytes of Flash/EE
data memory.
Results in the erase of the entire 56 Kbytes of ULOAD
Flash/EE program memory
81H
READBYTE
Results in the byte in the Flash/EE data memory,
addressed by the byte address EADRH/L, being read
into EDATA1. (0 ≤ EADRH/L ≤ 0FFFH).
Not Implemented. Use the MOVC command.
82H
WRITEBYTE
Results in the byte in EDATA1 being written into
Results in the byte in EDATA1 being written into
Flash/EE data memory, at the byte address EADRH/L. Flash/EE program memory at the byte address
EADRH/L (0 ≤ EADRH/L ≤ DFFFH)
0FH
EXULOAD
Leaves the ECON instructions to operate on the
Flash/EE data memory.
F0H
ULOAD
Enters ULOAD mode, directing subsequent ECON
Leaves the ECON Instructions to operate on the Flash/EE
instructions to operate on the Flash/EE program memory. program memory.
ECON Value
01H
READ
–32–
Enters normal mode directing subsequent ECON
instructions to operate on the Flash/EE data memory
REV. A
ADuC834
Programming the Flash/EE Data Memory
A user wishes to program F3H into the second byte on Page 03H
of the Flash/EE data memory space while preserving the other
three bytes already in this page.
A typical program of the Flash/EE data array will involve:
1. setting EADRH/L with the page address
2. writing the data to be programmed to the EDATA1–4
3. writing the ECON SFR with the appropriate command
Step 1: Set Up the Page Address
The two address registers EADRH and EADRL hold the high
byte address and the low byte address of the page to be addressed.
The assembly language to set up the address may appear as:
MOV EADRH,#0 ; Set Page Address Pointer
MOV EADRL,#03H
Flash/EE Memory Timing
Step 2: Set Up the EDATA Registers
The four values to be written into the page into the 4 SFRs
EDATA1–4. Unfortunately we do not know three of them. Thus it
is necessary to read the current page and overwrite the second byte.
; Read Page into EDATA1-4
MOV ECON,#1
MOV EDATA2,#0F3H ; Overwrite byte 2
Step 3: Program Page
A byte in the Flash/EE array can only be programmed if it has
previously been erased. To be more specific, a byte can only be
programmed if it already holds the value FFH. Because of the
Flash/EE architecture, this erase must happen at a page level.
Therefore, a minimum of 4 bytes (1 page) will be erased when
an erase command is initiated. Once the page is erased, we can
program the 4 bytes in-page and then perform a verification of
the data.
; ERASE Page
MOV ECON,#5
MOV ECON,#2
; WRITE Page
MOV ECON,#4
; VERIFY Page
MOV A,ECON
; Check if ECON=0 (OK!)
JNZ ERROR
REV. A
Note: although the 4 Kbytes of Flash/EE data memory is shipped
from the factory pre-erased, i.e., Byte locations set to FFH, it is
nonetheless good programming practice to include an erase-all
routine as part of any configuration/setup code running on the
ADuC834. An “ERASE-ALL” command consists of writing
“06H” to the ECON SFR, which initiates an erase of the 4-Kbyte
Flash/EE array. This command coded in 8051 assembly would
appear as:
MOV ECON,#06H
;
Erase all Command
; 2 ms Duration
Typical program and erase times for the ADuC834 are as follows:
Normal Mode (operating on Flash/EE data memory)
READPAGE (4 bytes)
– 5 machine cycles
WRITEPAGE (4 bytes)
– 380 s
VERIFYPAGE (4 bytes)
– 5 machine cycles
ERASEPAGE (4 bytes)
– 2 ms
ERASEALL (4 Kbytes)
– 2 ms
READBYTE (1 byte)
– 3 machine cycles
WRITEBYTE (1 byte)
– 200 s
ULOAD Mode (operating on Flash/EE program memory)
WRITEPAGE (256 bytes)
– 15 ms
ERASEPAGE (64 bytes)
– 2 ms
ERASEALL (56 Kbytes)
– 2 ms
WRITEBYTE (1 byte)
– 200 s
It should be noted that a given mode of operation is initiated as
soon as the command word is written to the ECON SFR. The
core microcontroller operation on the ADuC834 is idled until
the requested Program/Read or Erase mode is completed.
In practice, this means that even though the Flash/EE memory
mode of operation is typically initiated with a two-machine cycle
MOV instruction (to write to the ECON SFR), the next instruction
will not be executed until the Flash/EE operation is complete.
This means that the core will not respond to interrupt requests
until the Flash/EE operation is complete, although the core
peripheral functions like Counter/Timers will continue to count
and time as configured throughout this period.
–33–
ADuC834
DAC
The ADuC834 incorporates a 12-bit, voltage output DAC
on-chip. It has a rail-to-rail voltage output buffer capable of driving
10 kΩ/100 pF. It has two selectable ranges, 0 V to VREF (the internal bandgap 2.5 V reference) and 0 V to AVDD. It can operate in
12-bit or 8-bit mode. The DAC has a control register, DACCON,
and two data registers, DACH/L. The DAC output can be
programmed to appear at Pin 3 or Pin 12. It should be noted
that in 12-bit mode, the DAC voltage output will be updated as
soon as the DACL data SFR has been written; therefore, the
DAC data registers should be updated as DACH first, followed
by DACL. The 12-bit DAC data should be written into DACH/L
right-justified such that DACL contains the lower eight bits,
and the lower nibble of DACH contains the upper four bits.
Table XV. DACCON SFR Bit Designations
Bit
Name
Description
7
–––
Reserved for Future Use
6
–––
Reserved for Future Use
5
–––
Reserved for Future Use
4
DACPIN
DAC Output Pin Select.
Set by the user to direct the DAC output to Pin 12 (P1.7/AIN4/DAC).
Cleared by user to direct the DAC output to Pin 3 (P1.2/DAC/IEXC1).
3
DAC8
DAC 8-bit Mode Bit.
Set by user to enable 8-bit DAC operation. In this mode, the 8-bits in DACL SFR are routed
to the 8 MSBs of the DAC, and the 4 LSBs of the DAC are set to zero.
Cleared by user to operate the DAC in its normal 12-bit mode of operation.
2
DACRN
DAC Output Range Bit.
Set by user to configure DAC range of 0–AVDD.
Cleared by user to configure DAC range of 0 V–2.5 V (VREF).
1
DACCLR
DAC Clear Bit.
Set to 1 by user to enable normal DAC operation.
Cleared to 0 by user to reset DAC data registers DACL/H to zero.
0
DACEN
DAC Enable Bit.
Set to 1 by user to enable normal DAC operation.
Cleared to 0 by user to power down the DAC.
DACH/L
DAC Data Registers
Function
SFR Address
DAC Data Registers, written by user to update the DAC output.
DACL (DAC Data Low Byte)
FBH
DACH (DAC Data High Byte)
FCH
00H
Both Registers
No
Both Registers
Power-On Default Value
Bit Addressable
Using the D/A Converter
The on-chip D/A converter architecture consists of a resistor
string DAC followed by an output buffer amplifier, the functional equivalent of which is illustrated in Figure 21.
AVDD
VREF
ADuC834
R
OUTPUT
BUFFER
R
12 DAC
R
HIGH-Z
DISABLE
(FROM MCU)
R
R
Figure 21. Resistor String DAC Functional Equivalent
Features of this architecture include inherent guaranteed monotonicity and excellent differential linearity. As illustrated in
Figure 21, the reference source for the DAC is user selectable in
software. It can be either AVDD or VREF. In 0-to-AVDD mode,
the DAC output transfer function spans from 0 V to the voltage
at the AVDD pin. In 0-to-VREF mode, the DAC output transfer
function spans from 0 V to the internal VREF (2.5 V). The DAC
output buffer amplifier features a true rail-to-rail output stage
implementation. This means that, unloaded, each output is
capable of swinging to within less than 100 mV of both AVDD
and ground. Moreover, the DAC’s linearity specification (when
driving a 10 kΩ resistive load to ground) is guaranteed through
the full transfer function except codes 0 to 48 in 0-to-VREF
mode and 0 to 100 and 3950 to 4095 in 0-to-VDD mode.
Linearity degradation near ground and VDD is caused by saturation
of the output amplifier, and a general representation of its effects
(neglecting offset and gain error) is illustrated in Figure 22. The
dotted line in Figure 22 indicates the ideal transfer function, and
the solid line represents what the transfer function might look
like with endpoint nonlinearities due to saturation of the output
amplifier.
–34–
REV. A
ADuC834
Note that Figure 22 represents a transfer function in 0-to-VDD
mode only. In 0-to-VREF mode (with VREF < VDD), the lower
nonlinearity would be similar, but the upper portion of the
transfer function would follow the “ideal” line right to the end,
showing no signs of endpoint linearity errors.
4
OUTPUT VOLTAGE – V
DAC LOADED WITH 0FFF HEX
VDD
VDD–50mV
VDD–100mV
3
1
DAC LOADED WITH 0000 HEX
0
50mV
0mV
FFF Hex
000 Hex
Figure 22. Endpoint Nonlinearities Due to Amplifier
Saturation
The endpoint nonlinearities conceptually illustrated in Figure 22
get worse as a function of output loading. Most of the ADuC834
data sheet specifications assume a 10 kΩ resistive load to
ground at the DAC output. As the output is forced to source or
sink more current, the nonlinear regions at the top or bottom
(respectively) of Figure 22 become larger. With larger current
demands, this can significantly limit output voltage swing.
Figures 23 and 24 illustrate this behavior. It should be noted
that the upper trace in each of these figures is only valid for an
output range selection of 0-to-AVDD. In 0-to-VREF mode, DAC
loading will not cause high-side voltage drops as long as the
reference voltage remains below the upper trace in the corresponding figure. For example, if AVDD = 3 V and VREF = 2.5 V,
the high-side voltage will not be affected by loads less than 5 mA.
But somewhere around 7 mA, the upper curve in Figure 24
drops below 2.5 V (VREF) indicating that at these higher currents,
the output will not be capable of reaching VREF.
5
15
For larger loads, the current drive capability may not be
sufficient. In order to increase the source and sink current
capability of the DAC, an external buffer should be added, as
shown in Figure 25.
ADuC834
12
Figure 25. Buffering the DAC Output
The DAC output buffer also features a high impedance disable
function. In the chip’s default power-on state, the DAC is
disabled and its output is in a high impedance state (or “threestate”) where they remain inactive until enabled in software.
This means that if a zero output is desired during power-up or
power-down transient conditions, a pull-down resistor must be
added to each DAC output. Assuming this resistor is in place,
the DAC output will remain at ground potential whenever the
DAC is disabled.
DAC LOADED WITH 0FFF HEX
4
OUTPUT VOLTAGE – V
5
10
SOURCE/SINK CURRENT – mA
Figure 24. Source and Sink Current Capability
with VREF = VDD = 3 V
100mV
3
2
1
DAC LOADED WITH 0000 HEX
0
0
5
10
SOURCE/SINK CURRENT – mA
15
Figure 23. Source and Sink Current Capability
with VREF = AVDD = 5 V
REV. A
0
–35–
ADuC834
PULSEWIDTH MODULATOR (PWM)
The PWM on the ADuC834 is a highly flexible PWM offering
programmable resolution and input clock, and can be configured for any one of six different modes of operation. Two of
these modes allow the PWM to be configured as a - DAC
with up to 16 bits of resolution. A block diagram of the PWM is
shown in Figure 26.
12.583MHz
PWMCLK
32.768kHz
CLOCK
SELECT
PROGRAMMABLE
DIVIDER
32.768kHz/15
16-BIT PWM COUNTER
P1.1
PWM0H/L
PWMCON (as described below) controls the different modes of
operation of the PWM as well as the PWM clock frequency.
PWM0H/L and PWM1H/L are the data registers that determine
the duty cycles of the PWM outputs at P1.0 and P1.1.
To use the PWM user software, first write to PWMCON to
select the PWM mode of operation and the PWM input clock.
Writing to PWMCON also resets the PWM counter. In any of
the 16-bit modes of operation (Modes 1, 3, 4, 6), user software
should write to the PWM0L or PWM1L SFRs first. This value
is written to a hidden SFR. Writing to the PWM0H or PWM1H
SFRs updates both the PWMxH and the PWMxL SFRs but
does not change the outputs until the end of the PWM cycle in
progress. The values written to these 16-bit registers are then
used in the next PWM cycle.
P1.0
COMPARE
MODE
The PWM uses five SFRs: the control SFR, PWMCON, and four
data SFRs PWM0H, PWM0L, PWM1H, and PWM1L.
PWM1H/L
PWMCON
SFR Address
Power-On Default Value
Bit Addressable
PWM Control SFR
AEH
00H
No
Figure 26. PWM Block Diagram
Table XVI. PWMCON SFR Bit Designations
Bit
Name
Description
7
–––
Reserved for Future Use
6
MD2
PWM Mode Bits
5
MD1
The MD2/1/0 bits choose the PWM mode as follows:
4
MD0
MD2
0
0
0
0
1
1
1
1
3
CDIV1
PWM Clock Divider
2
CDIV0
Scale the clock source for the PWM counter as follows:
CDIV1
CDIV0 Description
0
0
PWM Counter = Selected Clock /1
0
1
PWM Counter = Selected Clock /4
1
0
PWM Counter = Selected Clock /16
1
1
PWM Counter = Selected Clock /64
1
CSEL1
PWM Clock Divider
0
CSEL0
Select the clock source for the PWM as follows:
CSEL1
CSEL0 Description
0
0
PWM Clock = fXTAL/15
0
1
PWM Clock = fXTAL
1
0
PWM Clock = External Input at P3.4/T0/PWMCLK
1
1
PWM Clock = fVCO (12.58 MHz)
MD1
0
0
1
1
0
0
1
1
MD0
0
1
0
1
0
1
0
1
–36–
Mode
Mode 0: PWM Disabled
Mode 1: Single Variable Resolution PWM
Mode 2: Twin 8-bit PWM
Mode 3: Twin 16-bit PWM
Mode 4: Dual NRZ 16-bit - DAC
Mode 5: Dual 8-bit PWM
Mode 6: Dual RZ 16-bit - DAC
Reserved for Future Use
REV. A
ADuC834
PWM1L
PWM MODES OF OPERATION
Mode 0: PWM Disabled
PWM COUNTER
The PWM is disabled, allowing P1.0 and P1.1 be used as normal.
PWM0H
PWM0L
Mode 1: Single-Variable Resolution PWM
In Mode 1, both the pulse length and the cycle time (period) are
programmable in user code, allowing the resolution of the PWM
to be variable.
PWM1H/L sets the period of the output waveform. Reducing
PWM1H/L reduces the resolution of the PWM output but
increases the maximum output rate of the PWM (e.g., setting
PWM1H/L to 65536 gives a 16-bit PWM with a maximum
output rate of 192 Hz (12.583 MHz/65536). Setting PWM1H/L
to 4096 gives a 12-bit PWM with a maximum output rate of
3072 Hz (12.583 MHz/4096)).
PWM0H/L sets the duty cycle of the PWM output waveform,
as shown in Figure 27.
PWM1H/L
PWM COUNTER
PWM0H/L
0
P1.0
Figure 27. PWM in Mode 1
Mode 2: Twin 8-Bit PWM
In Mode 2, the duty cycle of the PWM outputs and the resolution
of the PWM outputs are both programmable. The maximum
resolution of the PWM output is eight bits.
PWM1H
0
P1.0
P1.1
Figure 28. PWM Mode 2
Mode 3: Twin 16-Bit PWM
In Mode 3, the PWM counter is fixed to count from 0 to 65536
giving a fixed 16-bit PWM. Operating from the 12.58 MHz core
clock results in a PWM output rate of 192 Hz. The duty cycle
of the PWM outputs at P1.0 and P1.1 are independently
programmable.
As shown below, while the PWM counter is less than PWM0H/L,
the output of PWM0 (P1.0) is high. Once the PWM counter
equals PWM0H/L, then PWM0 (P1.0) goes low and remains
low until the PWM counter rolls over.
Similarly, while the PWM counter is less than PWM1H/L, the
output of PWM1 (P1.1) is high. Once the PWM counter equals
PWM1H/L, then PWM1 (P1.1) goes low and remains low until
the PWM counter rolls over.
In this mode, both PWM outputs are synchronized (i.e., once the
PWM counter rolls over to 0, both PWM0 (P1.0) and PWM1
(P1.1) will go high).
65536
PWM COUNTER
PWM1L sets the period for both PWM outputs. Typically this
will be set to 255 (FFh) to give an 8-bit PWM, although it is
possible to reduce this as necessary. A value of 100 could be
loaded here to give a percentage PWM (i.e., the PWM is accurate to 1%).
PWM1H/L
PWM0H/L
0
The outputs of the PWM at P1.0 and P1.1 are shown in the
diagram below. As can be seen, the output of PWM0 (P1.0) goes
low when the PWM counter equals PWM0L. The output of
PWM1 (P1.1) goes high when the PWM counter equals PWM1H
and goes low again when the PWM counter equals PWM0H.
Setting PWM1H to 0 ensures that both PWM outputs start
simultaneously.
REV. A
P1.0
P1.1
Figure 29. PWM Mode 3
–37–
ADuC834
Mode 4: Dual NRZ 16-Bit - DAC
PWM1L
PWM COUNTERS
Mode 4 provides a high speed PWM output similar to that of a
Σ-∆ DAC. Typically, this mode will be used with the PWM
clock equal to 12.58 MHz.
PWM1H
PWM0L
In this mode, P1.0 and P1.1 are updated every PWM clock
(80 ns in the case of 12.58 MHz). Over any 65536 cycles (16-bit
PWM) PWM0 (P1.0) is high for PWM0H/L cycles and low for
(65536 – PWM0H/L) cycles. Similarly PWM1 (P1.1) is high for
PWM1H/L cycles and low for (65536 – PWM1H/L) cycles.
0
1
1
1
0
1
Mode 6: Dual RZ 16-Bit - DAC
Mode 6 provides a high speed PWM output similar to that of a
Σ-∆ DAC. Mode 6 operates very similarly to Mode 4. However,
the key difference is that Mode 6 provides return to zero (RZ)
Σ-∆ DAC output. Mode 4 provides non-return-to-zero Σ-∆ DAC
outputs. The RZ mode ensures that any difference in the rise
and fall times will not affect the Σ-∆ DAC INL. However, the
RZ mode halves the dynamic range of the Σ-∆ DAC outputs from
0→AVDD to 0→AVDD/2. For best results, this mode should be
used with a PWM clock divider of 4.
1
80s
16-BIT
16-BIT
12.583MHz
P1.0
Figure 31. PWM Mode 5
PWM0H/L = C000H
CARRY OUT AT P1.0
0
P1.1
If PWM1H is set to 4010H (slightly above one quarter of FS),
then typically P1.1 will be low for three clocks and high for one
clock (each clock is approximately 80 ns). Over every 65536
clocks, the PWM will compromise for the fact that the output
should be slightly above one quarter of full scale by having a
high cycle followed by only two low cycles.
16-BIT
PWM0H
If PWM1H is set to 4010H (slightly above one quarter of FS)
then typically P1.1 will be low for three full clocks (3 80 ns),
high for half a clock (40 ns) and then low again for half a clock
(40 ns) before repeating itself. Over every 65536 clocks, the
PWM will compromise for the fact that the output should be
slightly above one quarter of full scale by leaving the output
high for two half clocks in four every so often.
LATCH
16-BIT
16-BIT
0
0
0
1
0
0
0
CARRY OUT AT P1.1
For faster DAC outputs (at lower resolution), write 0s to the
LSBs that are not required with a 1 in the LSB position. If, for
example, only 12-bit performance is required, write “0001” to
the 4 LSBs. This means that a 12-bit accurate Σ-∆ DAC output
can occur at 3 kHz. Similarly, writing 00000001 to the 8 LSBs
gives an 8-bit accurate Σ-∆ DAC output at 49 kHz.
16-BIT
80s
PWM1H/L = 4000H
Figure 30. PWM Mode 4
For faster DAC outputs (at lower resolution), write 0s to the
LSBs that are not required with a 1 in the LSB position. If, for
example, only 12-bit performance is required, write “0001” to
the 4 LSBs. This means that a 12-bit accurate Σ-∆ DAC output
can occur at 3 kHz. Similarly, writing 00000001 to the 8 LSBs
gives an 8-bit accurate Σ-∆ DAC output at 49 kHz.
PWM0H/L = C000H
CARRY OUT AT P1.0
0 1
16-BIT
1
1
0 1
1
318s
Mode 5: Dual 8-Bit PWM
16-BIT
16-BIT
In Mode 5, the duty cycle of the PWM outputs and the resolution of the PWM outputs are individually programmable. The
maximum resolution of the PWM output is eight bits.
3.146MHz
The output resolution is set by the PWM1L and PWM1H SFRs
for the P1.0 and P1.1 outputs respectively. PWM0L and
PWM0H sets the duty cycles of the PWM outputs at P1.0 and
P1.1, respectively. Both PWMs have the same clock source and
clock divider.
16-BIT
LATCH
16-BIT
0
0
0 1
0
0
0
CARRY OUT AT P1.1
16-BIT
318s
PWM1H/L = 4000H
Figure 32. PWM Mode 6
–38–
REV. A
ADuC834
ON-CHIP PLL
The ADuC834 is intended for use with a 32.768 kHz watch
crystal. A PLL locks onto a multiple (384) of this to provide a
stable 12.582912 MHz clock for the system. The core can operate at this frequency, or at binary submultiples of it, to allow
power saving in cases where maximum core performance is not
PLLCON
SFR Address
Power-On Default Value
Bit Addressable
required. The default core clock is the PLL clock divided by 8
or 1.572864 MHz. The ADC clocks are also derived from the
PLL clock, with the modulator rate being the same as the crystal oscillator frequency. The above choice of frequencies ensures
that the modulators and the core will be synchronous, regardless
of the core clock rate. The PLL control register is PLLCON.
PLL Control Register
D7H
03H
No
Table XVII. PLLCON SFR Bit Designations
Bit
Name
Description
7
OSC_PD
Oscillator Power-Down Bit.
Set by user to halt the 32 kHz oscillator in power-down mode.
Cleared by user to enable the 32 kHz oscillator in power-down mode.
This feature allows the TIC to continue counting even in power-down mode.
6
LOCK
PLL Lock Bit. This is a read-only bit.
Set automatically at power-on to indicate the PLL loop is correctly tracking the crystal clock. After
power down, this bit can be polled to wait for the PLL to lock.
Cleared automatically at power-on to indicate the PLL is not correctly tracking the crystal clock.
This may be due to the absence of a crystal clock or an external crystal at power-on. In this mode,
the PLL output can be 12.58 MHz ± 20%. After the ADuC834 wakes up from power-down,
user code may poll this bit, to wait for the PLL to lock. If LOCK = 0, then the PLL is not locked.
5
–––
Reserved for Future Use; Should Be Written with ‘0’
4
LTEA
Reading this bit returns the state of the external EA pin latched at reset or power-on.
3
FINT
Fast Interrupt Response Bit.
Set by user enabling the response to any interrupt to be executed at the fastest core clock frequency,
regardless of the configuration of the CD2–0 bits (see below). After user code has returned from an
interrupt, the core resumes code execution at the core clock selected by the CD2–0 bits.
Cleared by user to disable the fast interrupt response feature.
2
CD2
CPU (Core Clock) Divider Bits.
1
0
CD1
CD0
This number determines the frequency at which the microcontroller core will operate.
CD2
CD1
CD0
Core Clock Frequency (MHz)
0
0
0
12.582912
0
0
1
6.291456
0
1
0
3.145728
0
1
1
1.572864 (Default Core Clock Frequency)
1
0
0
0.786432
1
0
1
0.393216
1
1
0
0.196608
1
1
1
0.098304
REV. A
–39–
ADuC834
TIME INTERVAL COUNTER (WAKE-UP/RTC TIMER)
A time interval counter (TIC) is provided on-chip for:
• periodically waking the part up from power-down
• implementing a Real-Time Clock
• counting longer intervals than the standard 8051 compatible
timers are capable of
sheet.) If the ADuC834 is in power-down mode, again with TIC
interrupt enabled, the TII bit will wake up the device and resume
code execution by vectoring directly to the TIC interrupt service
vector address at 0053H. The TIC-related SFRs are described
below with a block diagram of the TIC shown in Figure 33.
The TIC is capable of timeout intervals ranging from 1/128th
second to 255 hours. Furthermore, this counter is clocked by the
crystal oscillator rather than the PLL and thus has the ability to
remain active in power-down mode and time long power-down
intervals. This has obvious applications for remote battery-powered
sensors where regular widely spaced readings are required.
The TIC counter can easily be used to generate a real-time
clock. The hardware will count in seconds, minutes, and hours;
however, user software will have to count in days, months, and
years. The current time can be written to the timebase SFRs
(HTHSEC, SEC, MIN, and HOUR) while TCEN is low. When
the RTC timer is enabled (TCEN is set), the TCEN bit itself
and the HTHSEC, SEC, MIN, and HOUR Registers are not
reset to 00H after a hardware or watchdog timer reset. This is to
prevent the need to recalibrate the real-time clock after a reset.
However, these registers will be reset to 00H after a power cycle
(independent of TCEN) or after any reset if TCEN is clear.
Six SFRs are associated with the time interval counter, TIMECON
being its control register. Depending on the configuration of the
IT0 and IT1 bits in TIMECON, the selected time counter register
overflow will clock the interval counter. When this counter is
equal to the time interval value loaded in the INTVAL SFR, the
TII bit (TIMECON.2) is set and generates an interrupt if enabled.
(See IEIP2 SFR description under Interrupt System in this data
TCEN
32.768kHz EXTERNAL CRYSTAL
ITS0, 1
8-BIT
PRESCALER
HUNDREDTHS COUNTER
HTHSEC
SECOND COUNTER
SEC
INTERVAL
TIMEBASE
SELECTION
MUX
TIEN
MINUTE COUNTER
MIN
HOUR COUNTER
HOUR
INTERVAL TIMEOUT
TIME INTERVAL COUNTER INTERRUPT
8-BIT
INTERVAL COUNTER
EQUAL?
INTVAL SFR
Figure 33. TIC, Simplified Block Diagram
Table XVIII. TIMECON SFR Bit Designations
Bit
Name
Description
7
6
5
4
–––
–––
ITS1
ITS0
3
STI
2
TII
1
TIEN
0
TCEN
Reserved for Future Use
Reserved for Future Use. For future product code compatibility, this bit should be written as a ‘1.’
Interval Timebase Selection Bits
Written by user to determine the interval counter update rate.
ITS1
ITS0
Interval Timebase
0
0
1/128 Second
0
1
Seconds
1
0
Minutes
1
1
Hours
Single Time Interval Bit.
Set by user to generate a single interval timeout. If set, a timeout will clear the TIEN bit.
Cleared by user to allow the interval counter to be automatically reloaded and start counting again at
each interval timeout.
TIC Interrupt Bit.
Set when the 8-bit Interval Counter matches the value in the INTVAL SFR.
Cleared by user software.
Time Interval Enable Bit.
Set by user to enable the 8-bit time interval counter.
Cleared by user to disable and clear the contents of the 8-bit interval counter. To ensure that the
8-bit interval counter is cleared TIEN must be held low for at least 30.5 s (32 kHz).
Time Clock Enable Bit.
Set by user to enable the time clock to the time interval counters.
Cleared by user to disable the 32 kHz clock to the TIC and clear the 8-bit prescaler and the HTHSEC,
SEC, MIN and HOURS SFRs. To ensure that these registers are cleared, TCEN must be held low for at
least 30.5 s (32 kHz). The time registers (HTHSEC, SEC, MIN, and HOUR) can only be written
while TCEN is low.
–40–
REV. A
ADuC834
INTVAL
User Time Interval Select Register
Function
SFR Address
Power-On Default Value
Reset Default Value
Bit Addressable
Valid Value
User code writes the required time interval to this register. When the 8-bit interval counter is equal
to the time interval value loaded in the INTVAL SFR, the TII bit (TIMECON.2) is set and generates
generates an interrupt if enabled. (See IEIP2 SFR description under Interrupt System in this
data sheet.)
A6H
00H
00H
No
0 to 255 decimal
HTHSEC
Hundredths Seconds Time Register
Function
SFR Address
Power-On Default Value
Reset Default Value
Bit Addressable
Valid Value
This register is incremented in (1/128) second intervals once TCEN in TIMECON is active.
The HTHSEC SFR counts from 0 to 127 before rolling over to increment the SEC time register.
A2H
00H
00H if TCEN = 0, Previous Value before reset if TCEN = 1
No
0 to 127 decimal
SEC
Seconds Time Register
Function
SFR Address
Power-On Default Value
Reset Default Value
Bit Addressable
Valid Value
This register is incremented in 1-second intervals once TCEN in TIMECON is active. The SEC
SFR counts from 0 to 59 before rolling over to increment the MIN time register.
A3H
00H
00H if TCEN = 0, Previous Value before reset if TCEN = 1
No
0 to 59 decimal
MIN
Minutes Time Register
Function
SFR Address
Power-On Default Value
Reset Default Value
Bit Addressable
Valid Value
This register is incremented in 1-minute intervals once TCEN in TIMECON is active.
The MIN counts from 0 to 59 before rolling over to increment the HOUR time register.
A4H
00H
00H if TCEN = 0, Previous Value before reset if TCEN = 1
No
0 to 59 decimal
HOUR
Hours Time Register
Function
This register is incremented in 1-hour intervals once TCEN in TIMECON is active.
The HOUR SFR counts from 0 to 23 before rolling over to 0.
A5H
00H
00H if TCEN = 0, Previous Value before reset if TCEN = 1
No
0 to 23 decimal
SFR Address
Power-On Default Value
Reset Default Value
Bit Addressable
Valid Value
REV. A
–41–
ADuC834
WATCHDOG TIMER
The purpose of the watchdog timer is to generate a device reset or
interrupt within a reasonable amount of time if the ADuC834
enters an erroneous state, possibly due to a programming error,
electrical noise, or RFI. The watchdog function can be disabled
by clearing the WDE (Watchdog Enable) bit in the Watchdog
Control (WDCON) SFR. When enabled; the watchdog circuit
will generate a system reset or interrupt (WDS) if the user program
fails to set the Watchdog (WDE) bit within a predetermined
WDCON
SFR Address
Power-On Default Value
Bit Addressable
amount of time (see PRE3–0 bits in WDCON). The watchdog
timer itself is a 16-bit counter that is clocked at 32.768 kHz. The
watchdog timeout interval can be adjusted via the PRE3–0 bits
in WDCON. Full control and status of the watchdog timer
function can be controlled via the Watchdog Timer Control SFR
(WDCON). The WDCON SFR can only be written by user
software if the double write sequence described in WDWR
below is initiated on every write access to the WDCON SFR.
Watchdog Timer Control Register
C0H
10H
Yes
Table XIX. WDCON SFR Bit Designations
Bit
Name
Description
7
PRE3
Watchdog Timer Prescale Bits.
6
PRE2
The Watchdog timeout period is given by the equation: tWD = (2PRE (29/fPLL))
5
PRE1
(0 ≤ PRE ≤ 7; fPLL = 32.768 kHz)
4
PRE0
PRE3 PRE2
0
0
0
0
0
0
0
0
0
1
0
1
0
1
0
1
1
0
PRE3–0 > 1001
3
WDIR
Watchdog Interrupt Response Enable Bit. If this bit is set by the user, the watchdog will generate an
interrupt response instead of a system reset when the watchdog timeout period has expired. This
interrupt is not disabled by the CLR EA instruction and it is also a fixed, high-priority interrupt. If the
watchdog is not being used to monitor the system, it can alternatively be used as a timer. The prescaler
is used to set the timeout period in which an interrupt will be generated.
(See also Note 1, Table XXXIX in the Interrupt System section.)
2
WDS
Watchdog Status Bit.
Set by the Watchdog Controller to indicate that a watchdog timeout has occurred.
Cleared by writing a 0 or by an external hardware reset. It is not cleared by a watchdog reset.
1
WDE
Watchdog Enable Bit.
Set by user to enable the watchdog and clear its counters. If a 1 is not written to this bit within the
watchdog timeout period, the watchdog will generate a reset or interrupt, depending on WDIR.
Cleared under the following conditions, User writes 0, Watchdog Reset (WDIR = 0);
Hardware Reset; PSM Interrupt.
0
WDWR
Watchdog Write Enable Bit.
To write data into the WDCON SFR involves a double instruction sequence. The WDWR bit must
be set and the very next instruction must be a write instruction to the WDCON SFR. For example:
CLR
EA
; disable interrupts while writing
; to WDT
SETB
WDWR
; allow write to WDCON
MOV
WDCON, #72h ; enable WDT for 2.0s timeout
SETB
EA
; enable interrupts again (if rqd)
PRE1
0
0
1
1
0
0
1
1
0
PRE0
0
1
0
1
0
1
0
1
0
Timeout Period (ms)
15.6
31.2
62.5
125
250
500
1000
2000
0.0
–42–
Action
Reset or Interrupt
Reset or Interrupt
Reset or Interrupt
Reset or Interrupt
Reset or Interrupt
Reset or Interrupt
Reset or Interrupt
Reset or Interrupt
Immediate Reset
Reserved
REV. A
ADuC834
POWER SUPPLY MONITOR
As its name suggests, the Power Supply Monitor, once enabled,
monitors both supplies (AVDD or DVDD) on the ADuC834. It will
indicate when any of the supply pins drop below one of four
user-selectable voltage trip points from 2.63 V to 4.63 V. For
correct operation of the Power Supply Monitor function, AVDD
must be equal to or greater than 2.7 V. Monitor function is
controlled via the PSMCON SFR. If enabled via the IEIP2 SFR,
the monitor will interrupt the core using the PSMI bit in the
PSMCON SFR. This bit will not be cleared until the failing power
supply has returned above the trip point for at least 250 ms. This
monitor function allows the user to save working registers to avoid
possible data loss due to the low supply condition, and also
ensures that normal code execution will not resume until a safe
supply level has been well established. The supply monitor is also
protected against spurious glitches triggering the interrupt circuit.
PSMCON
Power Supply Monitor Control Register
SFR Address
Power-On Default Value
Bit Addressable
DFH
DEH
No
Table XX. PSMCON SFR Bit Designations
Bit
Name
Description
7
CMPD
DVDD Comparator Bit.
This is a read-only bit and directly reflects the state of the DVDD comparator.
Read 1 indicates the DVDD supply is above its selected trip point.
Read 0 indicates the DVDD supply is below its selected trip point.
6
CMPA
5
PSMI
AVDD Comparator Bit.
This is a read-only bit and directly reflects the state of the AVDD comparator.
Read 1 indicates the AVDD supply is above its selected trip point.
Read 0 indicates the AVDD supply is below its selected trip point.
Power Supply Monitor Interrupt Bit.
This bit will be set high by the MicroConverter if either CMPA or CMPD are low, indicating low
analog or digital supply. The PSMI bit can be used to interrupt the processor. Once CMPD and/or
CMPA return (and remain) high, a 250 ms counter is started. When this counter timesout, the
PSMI interrupt is cleared. PSMI can also be written by the user. However, if either comparator
output is low, it is not possible for the user to clear PSMI.
4
TPD1
DVDD Trip Point Selection Bits.
3
TPD0
These bits select the DVDD trip point voltage as follows:
TPD1
TPD0 Selected DVDD Trip Point (V)
0
0
4.63
0
1
3.08
1
0
2.93
1
1
2.63
2
TPA1
AVDD Trip Point Selection Bits.
1
TPA0
These bits select the AVDD trip point voltage as follows:
TPA1TPA0 Selected AVDD Trip Point (V)
0
0
4.63
0
1
3.08
1
0
2.93
1
1
2.63
0
PSMEN
Power Supply Monitor Enable Bit.
Set to 1 by the user to enable the Power Supply Monitor Circuit.
Cleared to 0 by the user to disable the Power Supply Monitor Circuit.
REV. A
–43–
ADuC834
SERIAL PERIPHERAL INTERFACE
MISO (Master In, Slave Out Data I/O Pin), Pin 14
The ADuC834 integrates a complete hardware Serial Peripheral
Interface (SPI) interface on-chip. SPI is an industry-standard
synchronous serial interface that allows eight bits of data to be
synchronously transmitted and received simultaneously, i.e., full
duplex. It should be noted that the SPI pins SCLOCK and MOSI
are multiplexed with the I2C pins SCLOCK and SDATA. The
pins are controlled via the I2CCON SFR only if SPE is clear.
SPI can be configured for master or slave operation and typically
consists of four pins, namely:
The MISO (master in slave out) pin is configured as an input
line in Master mode and an output line in Slave mode. The
MISO line on the master (data in) should be connected to the
MISO line in the slave device (data out). The data is transferred
as byte-wide (8-bit) serial data, MSB first.
SCLOCK (Serial Clock I/O Pin), Pin 26
The master clock (SCLOCK) is used to synchronize the data
being transmitted and received through the MOSI and MISO
data lines. A single data bit is transmitted and received in each
SCLOCK period. Therefore, a byte is transmitted/received after
eight SCLOCK periods. The SCLOCK pin is configured as an
output in master mode and as an input in Slave mode. In master
mode the bit-rate, polarity, and phase of the clock are controlled
by the CPOL, CPHA, SPR0, and SPR1 bits in the SPICON SFR
(see Table XXI). In Slave mode the SPICON register will have to
be configured with the phase and polarity (CPHA and CPOL) as
the master as for both Master and Slave mode the data is transmitted
on one edge of the SCLOCK signal and sampled on the other.
MOSI (Master Out, Slave In Pin), Pin 27
The MOSI (master out slave in) pin is configured as an output
line in Master mode and an input line in Slave mode. The MOSI
line on the master (data out) should be connected to the MOSI line
in the slave device (data in). The data is transferred as byte-wide
(8-bit) serial data, MSB first.
SS (Slave Select Input Pin), Pin 13
The Slave Select (SS) input pin is only used when the ADuC834
is configured in SPI Slave mode. This line is active low. Data is only
received or transmitted in Slave mode when the SS pin is low,
allowing the ADuC834 to be used in single master, multislave SPI
configurations. If CPHA = 1, the SS input may be permanently
pulled low. With CPHA = 0, the SS input must be driven low
before the first bit in a byte wide transmission or reception and
return high again after the last bit in that byte wide transmission
or reception. In SPI Slave mode, the logic level on the external
SS pin (Pin 13), can be read via the SPR0 bit in the SPICON SFR.
The following SFR registers are used to control the SPI interface.
Table XXI. SPICON SFR Bit Designations
Bit
Name
Description
7
ISPI
SPI Interrupt Bit.
Set by MicroConverter at the end of each SPI transfer.
Cleared directly by user code or indirectly by reading the SPIDAT SFR
6
WCOL
Write Collision Error Bit.
Set by MicroConverter if SPIDAT is written to while an SPI transfer is in progress.
Cleared by user code.
5
SPE
SPI Interface Enable Bit.
Set by user to enable the SPI interface.
Cleared by user to enable the I2C interface.
4
SPIM
SPI Master/Slave Mode Select Bit.
Set by user to enable Master mode operation (SCLOCK is an output).
Cleared by user to enable Slave mode operation (SCLOCK is an input).
3
CPOL*
Clock Polarity Select Bit.
Set by user if SCLOCK idles high.
Cleared by user if SCLOCK idles low.
2
CPHA*
Clock Phase Select Bit.
Set by user if leading SCLOCK edge is to transmit data.
Cleared by user if trailing SCLOCK edge is to transmit data.
1
SPR1
SPI Bit-Rate Select Bits.
0
SPR0
These bits select the SCLOCK rate (bit-rate) in Master mode as follows:
SPR1
SPR0
Selected Bit Rate
0
0
fCORE/2
0
1
fCORE/4
1
0
fCORE/8
1
1
fCORE/16
In SPI Slave mode, i.e., SPIM = 0, the logic level on the external SS pin (Pin 13), can be read
via the SPR0 bit.
*The CPOL and CPHA bits should both contain the same values for master and slave devices.
–44–
REV. A
ADuC834
SPIDAT
SPI Data Register
Function
The SPIDAT SFR is written by the user to transmit data over the SPI interface or read by user
code to read data just received by the SPI interface.
F7H
00H
No
SFR Address
Power-On Default Value
Bit Addressable
Using the SPI Interface
SPI Interface—Master Mode
Depending on the configuration of the bits in the SPICON SFR
shown in Table XXI, the ADuC834 SPI interface will transmit
or receive data in a number of possible modes. Figure 34 shows
all possible ADuC834 SPI configurations and the timing relationships and synchronization between the signals involved.
Also shown in this figure is the SPI interrupt bit (ISPI) and how
it is triggered at the end of each byte-wide communication.
In Master Mode, the SCLOCK pin is always an output and
generates a burst of eight clocks whenever user code writes to
the SPIDAT Register. The SCLOCK bit rate is determined by
SPR0 and SPR1 in SPICON. It should also be noted that the
SS Pin is not used in Master mode. If the ADuC834 needs to
assert the SS Pin on an external slave device, a port digital output
pin should be used.
SCLOCK
(CPOL = 1)
SCLOCK
(CPOL = 0)
SS
SAMPLE INPUT
(CPHA = 1)
DATA OUTPUT
? MSB BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 LSB
SPI Interface—Slave Mode
ISPI FLAG
SAMPLE INPUT
DATA OUTPUT
MSB BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 LSB ?
(CPHA = 0)
ISPI FLAG
Figure 34. SPI Timing, All Modes
REV. A
In Master Mode, a byte transmission or reception is initiated by
a write to SPIDAT. Eight clock periods are generated via the
SCLOCK pin and the SPIDAT byte being transmitted via
MOSI. With each SCLOCK period, a data bit is also sampled
via MISO. After eight clocks, the transmitted byte will have
been completely transmitted and the input byte will be waiting
in the input shift register. The ISPI flag will be set automatically
and an interrupt will occur if enabled. The value in the shift
register will be latched into SPIDAT.
In Slave Mode, the SCLOCK is an input. The SS pin must also
be driven low externally during the byte communication. Transmission is also initiated by a write to SPIDAT. In Slave Mode,
a data bit is transmitted via MISO and a data bit is received via
MOSI through each input SCLOCK period. After eight clocks,
the transmitted byte will have been completely transmitted and
the input byte will be waiting in the input shift register. The ISPI
flag will be set automatically and an interrupt will occur if enabled.
The value in the shift register will be latched into SPIDAT
only when the transmission/reception of a byte has been completed. The end of transmission occurs after the eighth clock has
been received, if CPHA = 1 or when SS returns high if CPHA = 0.
–45–
ADuC834
I2C SERIAL INTERFACE
The ADuC834 supports a fully licensed* I2C serial interface. The
I2C interface is implemented as a full hardware slave and software
master. SDATA (Pin 27) is the data I/O pin and SCLOCK
(Pin 26) is the serial clock. These two pins are shared with the
MOSI and SCLOCK pins of the on-chip SPI interface. Therefore
the user can only enable one or the other interface at any given
time (see SPE in Table XXI). Application Note uC001 describes
the operation of this interface as implemented and is available from
the MicroConverter website at www.analog.com/microconverter.
Three SFRs are used to control the I2C interface. These are described below.
I2CCON
SFR Address
Power-On Default Value
Bit Addressable
I2C Control Register
E8H
00H
Yes
Table XXII. I2CCON SFR Bit Designations
Bit
Name
Description
7
MDO
I2C Software Master Data Output Bit (Master Mode Only).
This data bit is used to implement a master I2C transmitter interface in software. Data written to this
bit will be outputted on the SDATA pin if the data output enable (MDE) bit is set.
6
MDE
I2C Software Master Data Output Enable Bit (Master Mode Only).
Set by the user to enable the SDATA pin as an output (Tx).
Cleared by the user to enable SDATA pin as an input (Rx).
5
MCO
I2C Software Master Clock Output Bit (Master Mode Only).
This data bit is used to implement a master I2C transmitter interface in software. Data written to
this bit will be outputted on the SCLOCK pin.
4
MDI
3
I2CM
I2C Software Master Data Input Bit (Master Mode Only).
This data bit is used to implement a master I2C receiver interface in software. Data on the SDATA
pin is latched into this bit on SCLOCK if the data output enable (MDE) bit is 0.
I2C Master/Slave Mode Bit.
Set by the user to enable I2C software master mode.
Cleared by user to enable I2C hardware slave mode.
2
I2CRS
I2C Reset Bit (Slave Mode Only).
Set by the user to reset the I2C interface.
Cleared by user code for normal I2C operation.
1
I2CTX
I2C Direction Transfer Bit (Slave Mode Only).
Set by the MicroConverter if the interface is transmitting.
Cleared by the MicroConverter if the interface is receiving.
0
I2CI
I2C Interrupt Bit (Slave Mode Only).
Set by the MicroConverter after a byte has been transmitted or received.
Cleared automatically when the user code reads the I2CDAT SFR (see I2CDAT below).
I2CADD
Function
SFR Address
Power-On Default Value
Bit Addressable
I2CDAT
Function
SFR Address
Power-On Default Value
Bit Addressable
I2C Address Register
Holds the I2C peripheral address for the part. It may be overwritten by the user code. Application Note uC001
at www.analog.com/microconverter describes the format of the I2C standard 7-bit address in detail.
9BH
55H
No
I2C Data Register
The I2CDAT SFR is written by the user to transmit data over the I2C interface or read by user code to
read data just received by the I2C interface. Accessing I2CDAT automatically clears any pending I2C
interrupt and the I2CI bit in the I2CCON SFR. User software should only access I2CDAT once per
interrupt cycle.
9AH
00H
No
* Purchase of licensed I2C components of Analog Devices or one of its sublicensed associated companies conveys a license for the purchaser under the Philips I2C
Patent Rights to use these components in an I2C system provided that the system conforms to the I2C Standard Specification as defined by Philips.
–46–
REV. A
ADuC834
Once enabled in I2C slave mode, the slave controller waits for a
START condition. If the ADuC834 detects a valid start condition,
followed by a valid address, and by the R/W bit, the I2CI interrupt bit will get automatically set by hardware.
The main features of the MicroConverter I2C interface are:
• Only two bus lines are required; a serial data line (SDATA)
and a serial clock line (SCLOCK).
•
An I2C master can communicate with multiple slave devices.
Because each slave device has a unique 7-bit address then
single master/slave relationships can exist at all times even in
a multislave environment (Figure 35).
•
On-chip filtering rejects <50 ns spikes on the SDATA and
the SCLOCK lines to preserve data integrity.
The I2C peripheral will only generate a core interrupt if the user
has preconfigured the I2C interrupt enable bit in the IEIP2 SFR
as well as the global interrupt bit EA in the IE SFR, i.e.,
; Enabling I2C Interrupts for the ADuC834
MOV IEIP2,#01h
; enable I2C interrupt
SETB EA
DVDD
I2C
MASTER
On the ADuC834 an auto clear of the I2CI bit is implemented
so this bit is cleared automatically on a read or write access to
the I2CDAT SFR.
I2C
SLAVE #1
MOV
I2CDAT, A
; I2CI auto-cleared MOV
A, I2CDAT
; I2CI auto-cleared
I2C
SLAVE #2
If for any reason the user tries to clear the interrupt more than
once, i.e., access the data SFR more than once per interrupt,
then the I2C controller will halt. The interface will then have to
be reset using the I2CRS bit.
Figure 35. Typical I2C System
Software Master Mode
The ADuC834 can be used as a I2C master device by configuring
the I2C peripheral in master mode and writing software to output
the data bit by bit, which is referred to as a software master. Master
mode is enabled by setting the I2CM bit in the I2CCON register.
To transmit data on the SDATA line, MDE must be set to enable
the output driver on the SDATA pin. If MDE is set then the
SDATA pin will be pulled high or low depending on whether the
MDO bit is set or cleared. MCO controls the SCLOCK pin and
is always configured as an output in Master mode. In Master
mode, the SCLOCK pin will be pulled high or low depending
on the whether MCO is set or cleared.
To receive data, MDE must be cleared to disable the output
driver on SDATA. Software must provide the clocks by toggling
the MCO bit and read SDATA pin via the MDI bit. If MDE is
cleared, MDI can be used to read the SDATA pin. The value of
the SDATA pin is latched into MDI on a rising edge of SCLOCK.
MDI is set if the SDATA pin was high on the last rising edge of
SCLOCK. MDI is clear if the SDATA pin was low on the last
rising edge of SCLOCK.
Software must control MDO, MCO, and MDE appropriately to
generate the START condition, slave address, acknowledge bits,
data bytes, and STOP conditions appropriately. These functions
are provided in Application Note uC001.
Hardware Slave Mode
After reset, the ADuC834 defaults to hardware slave mode. The
I2C interface is enabled by clearing the SPE bit in SPICON.
Slave mode is enabled by clearing the I2CM bit in I2CCON.
The ADuC834 has a full hardware slave. In slave mode, the I2C
address is stored in the I2CADD register. Data received or to be
transmitted is stored in the I2CDAT register.
REV. A
The user can choose to poll the I2CI bit or enable the interrupt.
In the case of the interrupt, the PC counter will vector to 003BH
at the end of each complete byte. For the first byte when the
user gets to the I2CI ISR, the 7-bit address and the R/W bit will
appear in the I2CDAT SFR.
The I2CTX bit contains the R/W bit sent from the master. If
I2CTX is set then the master would like to receive a byte. Hence
the slave will transmit data by writing to the I2CDAT register.
If I2CTX is cleared, the master would like to transmit a byte.
Hence the slave will receive a serial byte. The software can
interrogate the state of I2CTX to determine whether it should
write to or read from I2CDAT.
Once the ADuC834 has received a valid address, hardware will
hold SCLOCK low until the I2CI bit is cleared by the software.
This allows the master to wait for the slave to be ready before
transmitting the clocks for the next byte.
The I2CI interrupt bit will be set every time a complete data
byte is received or transmitted provided it is followed by a valid
ACK. If the byte is followed by a NACK, an interrupt is NOT
generated. The ADuC834 will continue to issue interrupts for
each complete data byte transferred until a STOP condition is
received or the interface is reset.
When a STOP condition is received, the interface will reset to a
state where it is waiting to be addressed (idle). Similarly, if the
interface receives a NACK at the end of a sequence, it also
returns to the default idle state. The I2CRS bit can be used to
reset the I2C interface. This bit can be used to force the interface back to the default idle state.
It should be noted that there is no way (in hardware) to distinguish between an interrupt generated by a received START +
valid address and an interrupt generated by a received data byte.
User software must be used to distinguish between these interrupts.
–47–
ADuC834
DUAL DATA POINTER
The ADuC834 incorporates two data pointers. The second data
pointer is a shadow data pointer and is selected via the data
pointer control SFR (DPCON). DPCON also includes features
such as automatic hardware post-increment and post-decrement,
as well as automatic data pointer toggle. DPCON is described
in Table XXIII.
DPCON
SFR Address
Power-On Default Value
Bit Addressable
Data Pointer Control SFR
A7H
00H
No
Table XXIII. DPCON SFR Bit Designations
Bit
Name
Description
7
–––
Reserved for Future Use
6
DPT
Data Pointer Automatic Toggle Enable.
Cleared by user to disable auto swapping of the DPTR.
Set in user software to enable automatic toggling of the DPTR after each MOVX or MOVC instruction.
5
DP1m1
Shadow Data Pointer Mode
4
DP1m0
These two bits enable extra modes of the shadow data pointer operation allowing for more compact
and more efficient code size and execution.
m1
m0
Behavior of the Shadow Data Pointer
0
0
8052 Behavior
0
1
DPTR is post-incremented after a MOVX or a MOVC instruction
1
0
DPTR is post-decremented after a MOVX or MOVC instruction
1
1
DPTR LSB is toggled after a MOVX or MOVC instruction
(This instruction can be useful for moving 8-bit blocks to/from 16-bit devices)
3
DP0m1
Main Data Pointer Mode
2
DP0m0
These two bits enable extra modes of the main data pointer operation allowing for more compact and
more efficient code size and execution.
m1
m0
Behavior of the Main Data Pointer
0
0
8052 Behavior
0
1
DPTR is post-incremented after a MOVX or a MOVC instruction
1
0
DPTR is post-decremented after a MOVX or MOVC instruction
1
1
DPTR LSB is toggled after a MOVX or MOVC instruction
(This instruction can be useful for moving 8-bit blocks to/from 16-bit devices)
1
–––
This bit is not implemented to allow the INC DPCON instruction toggle the data pointer without
incrementing the rest of the SFR.
0
DPSEL
Data Pointer Select.
Cleared by user to select the main data pointer. This means that the contents of the main 24-bit DPTR
appears in the 3 SFRs DPL, DPH, and DPP.
Set by the user to select the shadow data pointer. This means that the contents of the shadow 24-bit
DPTR appears in the 3 SFRs DPL, DPH, and DPP.
NOTES
1. This is the only place where the main and shadow data pointers are distinguished. Everywhere else in this data sheet, wherever the DPTR is mentioned, operation
on the active DPTR is implied.
2. Only MOVC/MOVX @DPTR instructions are relevant above. MOVC/MOVX PC/@Ri instructions will not cause the DPTR to automatically post increment/decrement,
and so on. To illustrate the operation of DPCON, the following code will copy 256 bytes of code memory at Address D000h into XRAM starting from Address 0000h.
the code uses 16 bytes and 2054 cycles. To perform this on a standard 8051 requires approximately 33 bytes and 7172 cycles (depending on how it is implemented).
MOV
MOV
DPTR,#0
DPCON,#55h
MOV
DPTR,#0D000h
;
;
;
;
;
;
Main DPTR = 0
Select shadow DPTR
DPTR1 increment mode,
DPTR0 increment mode
DPTR auto toggling ON
Shadow DPTR = D000h
MOVELOOP:
CLR A
MOVC A,@A+DPTR
MOVX @DPTR,A
MOV
JNZ
–48–
;
;
;
;
;
;
Get data
Post Inc DPTR
Swap to Main DPTR (Data)
Put ACC in XRAM
Increment main DPTR
Swap to Shad DPTR (Code)
A, DPL
MOVELOOP
REV. A
ADuC834
8052 COMPATIBLE ON-CHIP PERIPHERALS
Port 1
This section gives a brief overview of the various secondary
peripheral circuits that are also available to the user on-chip.
These remaining functions are mostly 8052 compatible (with a
few additional features) and are controlled via standard 8052
SFR bit definitions.
Port 1 is also an 8-bit port directly controlled via the P1 SFR.
The Port 1 pins are divided into two distinct pin groupings P1.0
to P1.1 and P1.2 to P1.7.
P1.0 and P1.1
P1.0 and P1.1 are bidirectional digital I/O pins with internal
pull-ups.
Parallel I/O
The ADuC834 uses four input/output ports to exchange data
with external devices. In addition to performing general-purpose
I/O, some ports are capable of external memory operations while
others are multiplexed with alternate functions for the peripheral
features on the device. In general, when a peripheral is enabled,
that pin may not be used as a general-purpose I/O pin.
Port 0
Port 0 is an 8-bit open-drain bidirectional I/O port that is directly
controlled via the Port 0 SFR. Port 0 is also the multiplexed low
order address and databus during accesses to external program
or data memory.
Figure 36 shows a typical bit latch and I/O buffer for a Port 0 port
pin. The bit latch (one bit in the port’s SFR) is represented as a
Type D flip-flop, which will clock in a value from the internal bus
in response to a “write to latch” signal from the CPU. The Q output
of the flip-flop is placed on the internal bus in response to a
“read latch” signal from the CPU. The level of the port pin itself
is placed on the internal bus in response to a “read pin” signal
from the CPU. Some instructions that read a port activate the
“read latch” signal, and others activate the “read pin” signal.
See the following Read-Modify-Write Instructions section for
more details.
ADDR/DATA
INTERNAL
BUS
WRITE
TO LATCH
These pins also have various secondary functions described in
Table XXIV. The timer 2 alternate functions of P1.0 and P1.1
can only be activated if the corresponding bit latch in the P1
SFR contains a 1. Otherwise, the port pin is stuck at 0. In the
case of the PWM outputs at P1.0 and P1.1, the PWM outputs
will overwrite anything written to P1.0 or P1.1.
Table XXIV. P1.0 and P1.1 Alternate Pin Functions
Pin
Alternate Function
P1.0
T2 (Timer/Counter 2 External Input)
PWM0 (PWM0 output at this pin)
T2EX (Timer/Counter 2 Capture/Reload Trigger)
PWM1 (PWM1 output at this pin)
P1.1
Figure 37 shows a typical bit latch and I/O buffer for a P1.0 or
P1.1 port pin. No external memory access is required from
either of these pins although internal pull-ups are present.
DVDD
CONTROL
READ
LATCH
If P1.0 and P1.1 have 1s written to them via the P1 SFR, these
pins are pulled high by the internal pull-up resistors. In this state,
they can also be used as inputs. As input pins being externally
pulled low, they will source current because of the internal
pull-ups. With 0s written to them, both these pins will drive a
logic low output voltage (VOL) and will be capable of sinking
10 mA compared to the standard 1.6 mA sink capability on the
other port pins.
P0.x
PIN
D
DVDD
Q
ALTERNATE
OUTPUT FUNCTION
READ
LATCH
CL Q
LATCH
INTERNAL
BUS
READ
PIN
D
WRITE
TO LATCH
In general-purpose I/O port mode, Port 0 pins that have 1s
written to them via the Port 0 SFR will be configured as opendrain and will therefore float. In this state, Port 0 pins can be
used as high impedance inputs. This is represented in Figure 36
by the NAND gate whose output remains high as long as the
CONTROL signal is low, thereby disabling the top FET. External pull-up resistors are therefore required when Port 0 pins are
used as general-purpose outputs. Port 0 pins with 0s written to
them will drive a logic low output voltage (VOL) and will be
capable of sinking 1.6 mA.
REV. A
P1.x
PIN
Q
CL Q
LATCH
Figure 36. Port 0 Bit Latch and I/O Buffer
As shown in Figure 36, the output drivers of Port 0 pins are
switchable to an internal ADDR and ADDR/DATA bus by an
internal CONTROL signal for use in external memory accesses.
During external memory accesses, the P0 SFR gets 1s written to
it (i.e., all of its bit latches become 1). When accessing external
memory, the CONTROL signal in Figure 36 goes high, enabling
push-pull operation of the output pin from the internal address
or databus (ADDR/DATA line). Therefore, no external pull-ups
are required on Port 0 in order for it to access external memory.
INTERNAL
PULL-UP*
READ
PIN
ALTERNATE
INPUT
FUNCTION
*SEE FIGURE 38
FOR DETAILS OF
INTERNAL PULL-UP
Figure 37. P1.0 and P1.1 Bit Latch and I/O Buffer
The internal pull-up consists of active circuitry as shown in
Figure 38. Whenever a P1.0 or P1.1 bit latch transitions from
low to high, Q1 in Figure 38 turns on for 2 oscillator periods to
quickly pull the pin to a logic high state. Once there, the weaker
Q3 turns on, thereby latching the pin to a logic high. If the pin
is momentarily pulled low externally, Q3 will turn off, but the
very weak Q2 will continue to source some current into the pin,
attempting to restore it to a logic high.
–49–
DVDD
2 CLK
DELAY
Q
FROM
PORT
LATCH
Q1
Q4
DVDD
Q2
DVDD
Q3
Px.x
PIN
Figure 38. Internal Pull-Up Configuration
ADuC834
P1.2 to P1.7
The remaining Port 1 pins (P1.2–P1.7) can only be configured as
analog input (ADC) or digital input pins. By (power-on) default,
these pins are configured as analog inputs, i.e., ‘1’ written in the
corresponding Port 1 register bit. To configure any of these pins
as digital inputs, the user should write a ‘0’ to these port bits to
configure the corresponding pin as a high impedance digital
input. Figure 39 illustrates this function. Note that there are no
output drivers for Port 1 pins, and they therefore cannot be
used as outputs.
Port 3 pins also have various secondary functions described in
Table XXV. The alternate functions of Port 3 pins can only be
activated if the corresponding bit latch in the P3 SFR contains a 1.
Otherwise, the port pin is stuck at 0.
Table XXV. Port 3, Alternate Pin Functions
Pin
Alternate Function
P3.0
RxD (UART Input Pin)
(or Serial Data I/O in Mode 0)
TxD (UART Output Pin)
(or Serial Clock Output in Mode 0)
INT0 (External Interrupt 0)
INT1 (External Interrupt 1)
T0 (Timer/Counter 0 External Input)
PWMCLK (PWM External Clock)
T1 (Timer/Counter 1 External Input)
WR (External Data Memory Write Strobe)
RD (External Data Memory Read Strobe)
P3.1
READ
LATCH
INTERNAL
BUS
WRITE
TO LATCH
D
Q
CL
Q
P3.2
P3.3
P3.4
LATCH
READ
PIN
TO ADC
P3.5
P3.6
P3.7
P1.x
PIN
Figure 39. P1.2 to P1.7 Bit Latch and I/O Buffer
Port 3 pins have the same bit latch and I/O buffer configurations
as the P1.0 and P1.1 as shown in Figure 41. The internal pull-up
configuration is also defined by that in Figure 38.
Port 2
Port 2 is a bidirectional port with internal pull-up resistors directly
controlled via the P2 SFR. Port 2 also emits the high order
address bytes during fetches from external program memory
and middle and high order address bytes during accesses to the
24-bit external data memory space.
DVDD
READ
LATCH
As shown in Figure 40, the output drivers of Ports 2 are switchable to an internal ADDR bus by an internal CONTROL signal
for use in external memory accesses (as for Port 0). In external
memory addressing mode (CONTROL = 1), the port pins
feature push/pull operation controlled by the internal address
bus (ADDR line). However unlike the P0 SFR during external
memory accesses, the P2 SFR remains unchanged.
INTERNAL
BUS
WRITE
TO LATCH
ADDR
CONTROL
INTERNAL
BUS
WRITE
TO LATCH
Q
CL
Q
CL
Q
P3.x
PIN
ALTERNATE
INPUT
FUNCTION
*SEE FIGURE 38
FOR DETAILS OF
INTERNAL PULL-UP
Figure 41. Port 3 Bit Latch and I/O Buffer
Additional Digital I/O
In addition to the port pins, the dedicated SPI/I2C pins (SCLOCK
and SDATA/MOSI) also feature both input and output functions.
Their equivalent I/O architectures are illustrated in Figure 42
and Figure 44, respectively, for SPI operation and in Figure 43
and Figure 45 for I2C operation.
DVDD DVDD
Notice that in I2C mode (SPE = 0), the strong pull-up FET
(Q1) is disabled leaving only a weak pull-up (Q2) present. By
contrast, in SPI mode (SPE = 1), the strong pull-up FET (Q1)
is controlled directly by SPI hardware, giving the pin push/pull
capability.
P2.x
PIN
LATCH
READ
PIN
Q
READ
PIN
INTERNAL
PULL-UP*
D
D
INTERNAL
PULL-UP*
LATCH
In general-purpose I/O port mode, Port 2 pins that have 1s written
to them are pulled high by the internal pull-ups (Figure 38) and,
in that state, they can be used as inputs. As inputs, Port 2 pins
being pulled externally low will source current because of the
internal pull-up resistors. Port 2 pins with 0s written to them
will drive a logic low output voltage (VOL) and will be capable
of sinking 1.6 mA.
READ
LATCH
ALTERNATE
OUTPUT
FUNCTION
*SEE FIGURE 38 FOR
DETAILS OF INTERNAL PULL-UP
Port 3 is a bidirectional port with internal pull-ups directly
controlled via the P3 SFR.
In I2C mode (SPE = 0), two pull-down FETs (Q3 and Q4)
operate in parallel in order to provide an extra 60% or 70% of
current sinking capability. In SPI mode, however, (SPE = 1), only
one of the pull-down FETs (Q3) operates on each pin resulting
in sink capabilities identical to that of Port 0 and Port 2 pins.
Port 3 pins that have 1s written to them are pulled high by the
internal pull-ups and in that state they can be used as inputs. As
inputs, Port 3 pins being pulled externally low will source current
because of the internal pull-ups. Port 3 pins with 0s written to
them will drive a logic low output voltage (VOL) and will be
capable of sinking 1.6 mA.
On the input path of SCLOCK, notice that a Schmitt trigger
conditions the signal going to the SPI hardware to prevent false
triggers (double triggers) on slow incoming edges. For incoming
signals from the SCLOCK and SDATA pins going to I2C hardware, a filter conditions the signals in order to reject glitches of
up to 50 ns in duration.
Figure 40. Port 2 Bit Latch and I/O Buffer
Port 3
–50–
REV. A
ADuC834
Notice also that direct access to the SCLOCK and SDATA/MOSI
pins is afforded through the SFR interface in I2C master mode.
Therefore, if you are not using the SPI or I2C functions, you can
use these two pins to give additional high current digital outputs.
DVDD
SPE = 1 (SPI ENABLE)
As shown in Figure 46, the MISO pin in SPI master/slave
operation offers the exact same pull-up and pull-down configuration as the MOSI pin in SPI slave/master operation.
The SS pin has a weak internal pull-up permanently enabled to
prevent the SS input from floating. This pull-up can be easily
overdriven by an external device to drive the SS pin low.
Q1
DVDD
Q2 (OFF)
HARDWARE SPI
(MASTER/SLAVE)
SCLOCK
PIN
SCHMITT
TRIGGER
Q4 (OFF)
HARDWARE SPI
(MASTER/SLAVE)
Q3
MISO
PIN
Figure 42. SCLOCK Pin I/O Functional Equivalent in
SPI Mode
Figure 46. MISO Pin I/O Functional Equivalent
DVDD
SPE = 0 (I2C ENABLE)
DVDD
HARDWARE I2C
(SLAVE ONLY)
SFR
BITS
Q1
(OFF)
Q2
50ns GLITCH
REJECTION FILTER
HARDWARE SPI
(MASTER/SLAVE)
SCLOCK
PIN
MCO
Figure 47. SS Pin I/O Functional Equivalent
Q4
Q3
I2CM
Read-Modify-Write Instructions
Figure 43. SCLOCK Pin I/O Functional Equivalent in
I2C Mode
DVDD
SPE = 1 (SPI ENABLE)
Q1
Q2 (OFF)
SDATA/
MOSI
PIN
HARDWARE SPI
(MASTER/SLAVE)
Q4 (OFF)
Q3
Figure 44. SDATA/MOSI Pin I/O Functional Equivalent
in SPI Mode
DVDD
SPE = 0 (I2C ENABLE)
SFR
BITS
HARDWARE I2C
(SLAVE ONLY)
Q1
(OFF)
Q2
50ns GLITCH
REJECTION FILTER
SDATA/
MOSI
PIN
MDI
Q4
MDO
MDE
SS
PIN
Some 8051 instructions that read a port read the latch and
others read the pin. The instructions that read the latch rather
than the pins are the ones that read a value, possibly change it,
and then rewrite it to the latch. These are called “read-modifywrite” instructions. Listed below are the read-modify-write
instructions. When the destination operand is a port, or a port
bit, these instructions read the latch rather than the pin.
ANL
ORL
XRL
JBC
(Logical AND, e.g., ANL P1, A)
(Logical OR, e.g., ORL P2, A)
(Logical EX-OR, e.g., XRL P3, A)
(Jump If Bit = 1 and Clear Bit,
e.g., JBC P1.1, LABEL
CPL
(Complement Bit, e.g., CPL P3.0)
INC
(Increment, e.g., INC P2)
DEC
(Decrement, e.g., DEC P2)
DJNZ
(Decrement and Jump IFf Not Zero,
e.g.,DJNZ P3, LABEL)
MOV PX.Y, C* (Move Carry to Bit Y of Port X)
CLR PX.Y*
(Clear Bit Y of Port X)
SETB PX.Y*
(Set Bit Y of Port X)
The reason that read-modify-write instructions are directed to
the latch rather than the pin is to avoid a possible misinterpretation of the voltage level of a pin. For example, a port pin might
be used to drive the base of a transistor. When a 1 is written to
the bit, the transistor is turned on. If the CPU then reads the
same port bit at the pin rather then the latch, it will read the
base voltage of the transistor and interpret it as a Logic 0. Reading the latch rather than the pin will return the correct value of 1.
Q3
I2CM
Figure 45. SDATA/MOSI Pin I/O Functional Equivalent
in I2C Mode
REV. A
*These instruction read the port byte (all 8 bits), modify the addressed bit and
then write the new byte back to the latch.
–51–
ADuC834
In ‘Timer’ function, the TLx Register is incremented every
machine cycle. Thus it can be viewed as counting machine
cycles. Since a machine cycle consists of 12 core clock periods,
the maximum count rate is 1/12 of the core clock frequency.
S5P2 of every machine cycle. When the samples show a high in
one cycle and a low in the next cycle, the count is incremented.
The new count value appears in the register during S3P1 of the
cycle following the one in which the transition was detected.
Since it takes two machine cycles (16 core clock periods) to
recognize a 1-to-0 transition, the maximum count rate is 1/16 of
the core clock frequency. There are no restrictions on the duty
cycle of the external input signal, but to ensure that a given level
is sampled at least once before it changes, it must be held for a
minimum of one full machine cycle. Remember that the core
clock frequency is programmed via the CD0–2 selection bits in
the PLLCON SFR.
In ‘Counter’ function, the TLx Register is incremented by a
1-to-0 transition at its corresponding external input pin, T0,
T1, or T2. In this function, the external input is sampled during
User configuration and control of the timers is achieved via
three main SFRs. TMOD and TCON control the configuration
of Timers 0 and 1 while T2CON configures Timer 2.
TIMERS/COUNTERS
The ADuC834 has three 16-bit Timer/Counters: Timer 0,
Timer 1, and Timer 2. The Timer/Counter hardware has been
included on-chip to relieve the processor core of the overhead
inherent in implementing timer/counter functionality in software. Each Timer/Counter consists of two 8-bit registers THx
and TLx (x = 0, 1 and 2). All three can be configured to operate either as timers or event counters.
TMOD
Timer/Counter 0 and 1 Mode Register
SFR Address
Power-On Default Value
Bit Addressable
89H
00H
No
Table XXVI. TMOD SFR Bit Designations
Bit
Name
Description
7
Gate
Timer 1 Gating Control.
Set by software to enable timer/counter 1 only while INT1 pin is high and TR1 control bit is set.
Cleared by software to enable Timer 1 whenever TR1 control bit is set.
6
C/T
Timer 1 Timer or Counter Select Bit.
Set by software to select counter operation (input from T1 pin).
Cleared by software to select timer operation (input from internal system clock).
5
M1
Timer 1 Mode Select Bit 1 (used with M0 Bit)
4
M0
Timer 1 Mode Select Bit 0.
M1
M0
0
0
TH1 operates as an 8-bit timer/counter. TL1 serves as 5-bit prescaler.
0
1
16-Bit Timer/Counter. TH1 and TL1 are cascaded; there is no prescaler.
1
0
8-Bit Auto-Reload Timer/Counter. TH1 holds a value that is to be
reloaded into TL1 each time it overflows.
1
1
Timer/Counter 1 Stopped.
3
Gate
Timer 0 Gating Control.
Set by software to enable timer/counter 0 only while INT0 pin is high and TR0 control bit is set.
Cleared by software to enable Timer 0 whenever TR0 control bit is set.
2
C/T
1
M1
Timer 0 Timer or Counter Select Bit.
Set by software to select counter operation (input from T0 pin).
Cleared by software to select timer operation (input from internal system clock).
Timer 0 Mode Select Bit 1
0
M0
Timer 0 Mode Select Bit 0.
M1
M0
0
0
TH0 operates as an 8-bit timer/counter. TL0 serves as 5-bit prescaler.
0
1
16-Bit Timer/Counter. TH0 and TL0 are cascaded; there is no prescaler
1
0
8-Bit Auto-Reload Timer/Counter. TH0 holds a value that is to be
reloaded into TL0 each time it overflows.
1
1
TL0 is an 8-bit timer/counter controlled by the standard timer 0 control
bits. TH0 is an 8-bit timer only, controlled by Timer 1 control bits.
–52–
REV. A
ADuC834
TCON
Timer/Counter 0 and 1 Control Register
SFR Address
Power-On Default Value
Bit Addressable
88H
00H
Yes
Table XXVII. TCON SFR Bit Designations
Bit
Name
Description
7
TF1
Timer 1 Overflow Flag.
Set by hardware on a Timer/Counter 1 overflow.
Cleared by hardware when the Program Counter (PC) vectors to the interrupt service routine.
6
TR1
Timer 1 Run Control Bit.
Set by user to turn on Timer/Counter 1.
Cleared by user to turn off Timer/Counter 1.
5
TF0
Timer 0 Overflow Flag.
Set by hardware on a Timer/Counter 0 overflow.
Cleared by hardware when the PC vectors to the interrupt service routine.
4
TR0
Timer 0 Run Control Bit.
Set by user to turn on Timer/Counter 0.
Cleared by user to turn off Timer/Counter 0.
3
IE1*
External Interrupt 1 (INT1) Flag.
Set by hardware by a falling edge or zero level being applied to external interrupt pin INT1,
depending on bit IT1 state.
Cleared by hardware when the PC vectors to the interrupt service routine only if the interrupt
was transition-activated. If level-activated, the external requesting source controls the
request flag, rather than the on-chip hardware.
2
IT1*
External Interrupt 1 (IE1) Trigger Type.
Set by software to specify edge-sensitive detection (i.e., 1-to-0 transition).
Cleared by software to specify level-sensitive detection (i.e., zero level).
1
IE0*
External Interrupt 0 (INT0) Flag.
Set by hardware by a falling edge or zero level being applied to external interrupt pin INT0, depending
on bit IT0 state.
Cleared by hardware when the PC vectors to the interrupt service routine only if the interrupt was
transition-activated. If level-activated, the external requesting source controls the request flag,
rather than the on-chip hardware.
0
IT0*
External Interrupt 0 (IE0) Trigger Type.
Set by software to specify edge-sensitive detection (i.e., 1-to-0 transition).
Cleared by software to specify level-sensitive detection (i.e., zero level).
*These bits are not used in the control of timer/counter 0 and 1, but are used instead in the control and monitoring of the external INT0 and INT1 interrupt pins.
Timer/Counter 0 and 1 Data Registers
Both timer 0 and timer 1 consist of two 8-bit registers. These can be used as independent registers or combined to be a single 16-bit
register, depending on the timer mode configuration.
TH0 and TL0
Timer 0 high byte and low byte. SFR Address = 8CH, 8AH, respectively.
TH1 and TL1
Timer 1 high byte and low byte. SFR Address = 8DH, 8BH, respectively.
REV. A
–53–
ADuC834
TIMER/COUNTER 0 AND 1 OPERATING MODES
Mode 2 (8-Bit Timer/Counter with Auto Reload)
The following paragraphs describe the operating modes for
Timer/Counters 0 and 1. Unless otherwise noted, it should be
assumed that these modes of operation are the same for Timer 0
as for Timer 1.
Mode 2 configures the timer register as an 8-bit counter (TL0)
with automatic reload, as shown in Figure 50. Overflow from
TL0 not only sets TF0, but also reloads TL0 with the contents
of TH0, which are preset by software. The reload leaves TH0
unchanged.
Mode 0 (13-Bit Timer/Counter)
Mode 0 configures an 8-bit timer/counter with a divide-by-32
prescaler. Figure 48 shows Mode 0 operation.
CORE
CLK*
12
C/ T = 0
CORE
CLK*
TL0
(8 BITS)
12
C/ T = 0
TL0
TH0
(5 BITS) (8 BITS)
INTERRUPT
TF0
C/ T = 1
INTERRUPT
TF0
P3.4/T0
CONTROL
C/ T = 1
TR0
P3.4/T0
CONTROL
TR0
RELOAD
TH0
(8 BITS)
GATE
P3.2/INT0
*THE CORE CLOCK IS THE OUTPUT OF THE PLL (SEE "ON-CHIP PLL")
GATE
P3.2/INT0
Figure 50. Timer/Counter 0, Mode 2
*THE CORE CLOCK IS THE OUTPUT OF THE PLL (SEE "ON-CHIP PLL")
Mode 3 (Two 8-Bit Timer/Counters)
Figure 48. Timer/Counter 0, Mode 0
In this mode, the timer register is configured as a 13-bit register.
As the count rolls over from all 1s to all 0s, it sets the timer overflow flag. The overflow flag, TF0, can then be used to request
an interrupt. The counted input is enabled to the timer when
TR0 = 1 and either Gate = 0 or INT0 = 1. Setting Gate = 1 allows
the timer to be controlled by external input INT0, to facilitate
pulsewidth measurements. TR0 is a control bit in the special
function register TCON; Gate is in TMOD. The 13-bit register
consists of all eight bits of TH0 and the lower five bits of TL0.
The upper three bits of TL0 are indeterminate and should be
ignored. Setting the run flag (TR0) does not clear the registers.
Mode 1 (16-Bit Timer/Counter)
Mode 1 is the same as Mode 0, except that the timer register is
running with all 16 bits. Mode 1 is shown in Figure 49.
CORE
CLK*
Mode 3 has different effects on Timer 0 and Timer 1. Timer 1 in
Mode 3 simply holds its count. The effect is the same as setting
TR1 = 0. Timer 0 in Mode 3 establishes TL0 and TH0 as two
separate counters. This configuration is shown in Figure 51.
TL0 uses the timer 0 control bits: C/T, Gate, TR0, INT0, and
TF0. TH0 is locked into a timer function (counting machine
cycles) and takes over the use of TR1 and TF1 from Timer 1.
Thus, TH0 now controls the “Timer 1” interrupt. Mode 3 is
provided for applications requiring an extra 8-bit timer or counter.
When Timer 0 is in Mode 3, Timer 1 can be turned on and off
by switching it out of and into its own Mode 3, or can still be
used by the serial interface as a baud rate generator. In fact, it
can be used, in any application not requiring an interrupt from
Timer 1 itself.
CORE
CLK*
CORE
CLK/12
12
12
C/ T = 0
C/ T = 0
TL0
TH0
(8 BITS) (8 BITS)
INTERRUPT
TF0
INTERRUPT
TL0
(8 BITS)
TF0
TH0
(8 BITS)
TF1
C/ T = 1
C/ T = 1
P3.4/T0
CONTROL
P3.4/T0
TR0
CONTROL
TR0
GATE
GATE
P3.2/INT0
P3.2/INT0
*THE CORE CLOCK IS THE OUTPUT OF THE PLL (SEE "ON-CHIP PLL")
CORE
CLK/12
Figure 49. Timer/Counter 0, Mode 1
INTERRUPT
TR1
*THE CORE CLOCK IS THE OUTPUT OF THE PLL (SEE "ON-CHIP PLL")
Figure 51. Timer/Counter 0, Mode 3
–54–
REV. A
ADuC834
TIMER/COUNTER 2 OPERATING MODES
16-Bit Capture Mode
The following paragraphs describe the operating modes for
Timer/Counter 2. The operating modes are selected by bits in
the T2CON SFR as shown in Table XXIX.
In the Capture Mode, there are again two options, selected by bit
EXEN2 in T2CON. If EXEN2 = 0, Timer 2 is a 16-bit timer or
counter that, upon overflowing, sets bit TF2, the Timer 2 overflow bit, which can be used to generate an interrupt. If EXEN2 = 1,
Timer 2 still performs the above, but a l-to-0 transition on
external input T2EX causes the current value in the Timer 2
registers, TL2 and TH2, to be captured into registers RCAP2L
and RCAP2H, respectively. In addition, the transition at T2EX
causes bit EXF2 in T2CON to be set; EXF2, like TF2, can generate an interrupt. The Capture Mode is illustrated in Figure 53.
Table XXVIII. Timer 2 Operating Modes
RCLK (or) TCLK
CAP2
TR2
MODE
0
0
1
X
0
1
X
X
1
1
1
0
16-Bit Autoreload
16-Bit Capture
Baud Rate
OFF
The baud rate generator mode is selected by RCLK = 1 and/or
TCLK = 1.
16-Bit Autoreload Mode
In either case, if Timer 2 is being used to generate the baud rate,
the TF2 interrupt flag will not occur. Therefore Timer 2 interrupts
will not occur so they do not have to be disabled. However, in
this mode, the EXF2 flag can still cause interrupts and this can
be used as a third external interrupt.
In Autoreload Mode, there are two options, selected by bit
EXEN2 in T2CON. If EXEN2 = 0, when Timer 2 rolls over it
not only sets TF2 but also causes the Timer 2 registers to be
reloaded with the 16-bit value in registers RCAP2L and RCAP2H,
which are preset by software. If EXEN2 = 1, Timer 2 still performs
the above, but with the added feature that a 1-to-0 transition at
external input T2EX will also trigger the 16-bit reload and set
EXF2. The Autoreload Mode is illustrated in Figure 52.
CORE
CLK*
12
Baud rate generation will be described as part of the UART
serial port operation.
C/ T2 = 0
TL2
(8 BITS)
TH2
(8 BITS)
RCAP2L
RCAP2H
C/ T2 = 1
T2
PIN
CONTROL
TR2
RELOAD
TRANSITION
DETECTOR
TF2
TIMER
INTERRUPT
T2EX
PIN
EXF2
CONTROL
EXEN2
*THE CORE CLOCK IS THE OUTPUT OF THE PLL (SEE "ON-CHIP PLL")
Figure 52. Timer/Counter 2, 16-Bit Autoreload Mode
CORE
CLK*
12
C/ T2 = 0
TL2
(8 BITS)
TH2
(8 BITS)
TF2
C/ T2 = 1
T2
PIN
CONTROL
TR2
TIMER
INTERRUPT
CAPTURE
TRANSITION
DETECTOR
RCAP2L
RCAP2H
T2EX
PIN
EXF2
CONTROL
EXEN2
*THE CORE CLOCK IS THE OUTPUT OF THE PLL (SEE "ON-CHIP PLL")
Figure 53. Timer/Counter 2, 16-Bit Capture Mode
REV. A
–55–
ADuC834
T2CON
Timer/Counter 2 Control Register
SFR Address
Power-On Default Value
Bit Addressable
C8H
00H
Yes
Table XXIX. T2CON SFR Bit Designations
Bit
Name
Description
7
TF2
Timer 2 Overflow Flag.
Set by hardware on a Timer 2 overflow. TF2 will not be set when either RCLK or TCLK = 1.
Cleared by user software.
6
EXF2
Timer 2 External Flag.
Set by hardware when either a capture or reload is caused by a negative transition on T2EX and
EXEN2 = 1.
Cleared by user software.
5
RCLK
Receive Clock Enable Bit.
Set by user to enable the serial port to use Timer 2 overflow pulses for its receive clock in serial port
Modes 1 and 3.
Cleared by user to enable Timer 1 overflow to be used for the receive clock.
4
TCLK
Transmit Clock Enable Bit.
Set by user to enable the serial port to use Timer 2 overflow pulses for its transmit clock in serial port
Modes 1 and 3.
Cleared by user to enable Timer 1 overflow to be used for the transmit clock.
3
EXEN2
Timer 2 External Enable Flag.
Set by user to enable a capture or reload to occur as a result of a negative transition on T2EX if Timer 2
is not being used to clock the serial port.
Cleared by user for Timer 2 to ignore events at T2EX.
2
TR2
Timer 2 Start/Stop Control Bit.
Set by user to start Timer 2.
Cleared by user to stop Timer 2.
1
CNT2
Timer 2 Timer or Counter Function Select Bit.
Set by user to select counter function (input from external T2 Pin).
Cleared by user to select timer function (input from on-chip core clock).
0
CAP2
Timer 2 Capture/Reload Select Bit.
Set by user to enable captures on negative transitions at T2EX if EXEN2 = 1.
Cleared by user to enable auto reloads with Timer 2 overflows or negative transitions at T2EX when
EXEN2 = 1. When either RCLK = 1 or TCLK = 1, this bit is ignored and the timer is forced to
autoreload on Timer 2 overflow.
Timer/Counter 2 Data Registers
Timer/Counter 2 also has two pairs of 8-bit data registers associated with it. These are used as both timer data registers and timer
capture/reload registers.
TH2 and TL2
Timer 2, data high byte and low byte.
SFR Address = CDH, CCH, respectively.
RCAP2H and RCAP2L
Timer 2, Capture/Reload byte and low byte.
SFR Address = CBH, CAH, respectively.
–56–
REV. A
ADuC834
RxD(P3.0) and TxD(P3.1), while the SFR interface to the UART
comprises the following registers:
UART SERIAL INTERFACE
The serial port is full duplex, meaning it can transmit and
receive simultaneously. It is also receive-buffered, meaning it
can commence reception of a second byte before a previously
received byte has been read from the receive register. However,
if the first byte still has not been read by the time reception of
the second byte is complete, the first byte will be lost. The
physical interface to the serial data network is via Pins
SBUF
The serial port receive and transmit registers are both accessed
through the SBUF SFR (SFR address = 99H). Writing to SBUF
loads the transmit register and reading SBUF accesses a physically
separate receive register.
SCON
UART Serial Port Control Registers
SFR Address
Power-On Default Value
Bit Addressable
98H
00H
Yes
Table XXX. SCON SFR Bit Designations
Bit
Name
Description
7
SM0
UART Serial Mode Select Bits.
6
SM1
These bits select the Serial Port operating mode as follows:
SM0
SM1 Selected Operating Mode
0
0
Mode 0: Shift Register, fixed baud rate (fCORE/12)
0
1
Mode 1: 8-bit UART, variable baud rate
1
0
Mode 2: 9-bit UART, fixed baud rate (fCORE/64) or (fCORE/32)
1
1
Mode 3: 9-bit UART, variable baud rate
5
SM2
Multiprocessor Communication Enable Bit.
Enables multiprocessor communication in Modes 2 and 3. In Mode 0, SM2 should be cleared. In
Mode 1, if SM2 is set, RI will not be activated if a valid stop bit was not received. If SM2 is cleared,
RI will be set as soon as the byte of data has been received. In Modes 2 or 3, if SM2 is set, RI will not be
activated if the received ninth data bit in RB8 is 0. If SM2 is cleared, RI will be set as soon as the byte
of data has been received.
4
REN
Serial Port Receive Enable Bit.
Set by user software to enable serial port reception.
Cleared by user software to disable serial port reception.
3
TB8
Serial Port Transmit (Bit 9).
The data loaded into TB8 will be the ninth data bit that will be transmitted in Modes 2 and 3.
2
RB8
Serial Port Receiver Bit 9.
The ninth data bit received in Modes 2 and 3 is latched into RB8. For Mode 1, the stop bit is latched into RB8.
1
TI
Serial Port Transmit Interrupt Flag.
Set by hardware at the end of the eighth bit in Mode 0, or at the beginning of the stop bit in
Modes 1, 2, and 3.
TI must be cleared by user software.
0
RI
Serial Port Receive Interrupt Flag.
Set by hardware at the end of the eighth bit in Mode 0, or halfway through the stop bit in
Modes 1, 2, and 3.
RI must be cleared by software.
MACHINE
CYCLE 1
UART OPERATING MODES
Mode 0: 8-Bit Shift Register Mode
Mode 0 is selected by clearing both the SM0 and SM1 bits in the
SFR SCON. Serial data enters and exits through RxD. TxD outputs
the shift clock. Eight data bits are transmitted or received. Transmission is initiated by any instruction that writes to SBUF. The
data is shifted out of the RxD line. The 8 bits are transmitted
with the least-significant bit (LSB) first, as shown in Figure 54.
Reception is initiated when the Receive Enable bit (REN) is
1 and the Receive Interrupt bit (RI) is 0. When RI is cleared,
the data is clocked into the RxD line and the clock pulses are
output from the TxD line.
REV. A
MACHINE
CYCLE 2
S1 S2 S3 S4 S5 S6 S1 S2 S3 S4
MACHINE
CYCLE 7
MACHINE
CYCLE 8
S4 S5 S6 S1 S2 S3 S4 S5 S6
CORE
CLK
ALE
RxD
(DATA OUT)
DATA BIT 0
DATA BIT 1
DATA BIT 6
DATA BIT 7
TxD
(SHIFT CLOCK)
Figure 54. UART Serial Port Transmission, Mode 0
–57–
ADuC834
Mode 1: 8-Bit UART, Variable Baud Rate
Mode 1 is selected by clearing SM0 and setting SM1. Each data
byte (LSB first) is preceded by a start bit (0) and followed by a
stop bit (1). Therefore 10 bits are transmitted on TxD or received
on RxD. The baud rate can be set by Timer 1 or Timer 2 (or
both). Alternatively, a dedicated baud rate generator, Timer 3, is
provided on-chip to generate high speed, very accurate baud rates.
Transmission is initiated by writing to SBUF. The ‘write to
SBUF’ signal also loads a 1 (stop bit) into the ninth bit position
of the Transmit Shift Register. The data is output bit by bit until
the stop bit appears on TxD and the transmit interrupt flag (TI)
is automatically set as shown in Figure 55.
START
BIT
TxD
STOP BIT
D0
D1
D2
D3
D4
D5
D6
D7
TI
(SCON.1)
The ninth bit (stop bit) is clocked into RB8 in SCON
•
The Receiver Interrupt flag (RI) is set
RI = 0, and
•
Either SM2 = 0, or SM2 = 1 and the received stop bit = 1.
•
The ninth data bit is latched into RB8 in SCON
•
The Receiver Interrupt flag (RI) is set
if, and only if, the following conditions are met at the time the
final shift pulse is generated:
•
RI = 0, and
•
Either SM2 = 0, or SM2 = 1 and the received stop bit = 1.
In all four modes, transmission is initiated by any instruction that
uses SBUF as a destination register. Reception is initiated in
Mode 0 by the condition RI = 0 and REN = 1. Reception is
initiated in the other modes by the incoming start bit if REN = 1.
UART Serial Port Baud Rate Generation
Mode 0 Baud Rate Generation
if, and only if, the following conditions are met at the time the
final shift pulse is generated:
•
The eight bits in the Receive Shift Register are latched
into SBUF
Mode 3 is selected by setting both SM0 and SM1. In this mode,
the 8051 UART serial port operates in 9-bit mode with a variable
baud rate determined by either Timer 1 or Timer 2. The operation of the 9-bit UART is the same as for Mode 2, but the baud
rate can be varied as for Mode 1.
Reception is initiated when a 1-to-0 transition is detected on
RxD. Assuming a valid start bit was detected, character reception continues. The start bit is skipped and the eight data bits
are clocked into the serial port shift register. When all eight bits
have been clocked in, the following events occur:
•
•
Mode 3: 9-Bit UART with Variable Baud Rate
Figure 55. UART Serial Port Transmission, Mode 0
The eight bits in the receive shift register are latched into
SBUF
Reception for Mode 2 is similar to that of Mode 1. The eight
data bytes are input at RxD (LSB first) and loaded onto the
Receive Shift Register. When all eight bits have been clocked in,
the following events occur:
If either of these conditions is not met, the received frame is
irretrievably lost and RI is not set.
SET INTERRUPT i.e.,
READY FOR MORE DATA
•
The transmission will start at the next valid baud rate clock.
The TI flag is set as soon as the stop bit appears on TxD.
The baud rate in Mode 0 is fixed:
Mode 0 Baud Rate =
fCORE *
12
Mode 2 Baud Rate Generation
If either of these conditions is not met, the received frame is
irretrievably lost and RI is not set.
Mode 2: 9-Bit UART with Fixed Baud Rate
Mode 2 is selected by setting SM0 and clearing SM1. In this
mode, the UART operates in 9-bit mode with a fixed baud rate.
The baud rate is fixed at Core_Clk/64 by default, although by
setting the SMOD bit in PCON, the frequency can be doubled
to Core_Clk/32. Eleven bits are transmitted or received, a start
bit (0), eight data bits, a programmable ninth bit, and a stop bit
(1). The ninth bit is most often used as a parity bit, although it
can be used for anything, including a ninth data bit if required.
To transmit, the eight data bits must be written into SBUF. The
ninth bit must be written to TB8 in SCON. When transmission
is initiated, the eight data bits (from SBUF) are loaded onto the
transmit shift register (LSB first). The contents of TB8 are loaded
into the ninth bit position of the transmit shift register.
The baud rate in Mode 2 depends on the value of the SMOD
bit in the PCON SFR. If SMOD = 0, the baud rate is 1/64 of the
core clock. If SMOD = 1, the baud rate is 1/32 of the core clock:
Mode 2 Baud Rate =
fCORE * × 2SMOD
64
Mode 1 and 3 Baud Rate Generation
Traditionally, the baud rates in Modes 1 and 3 are determined
by the overflow rate in Timer 1 or Timer 2, or both (one for
transmit and the other for receive). On the ADuC834, however,
the baud rate can also be generated via a separate baud rate
generator to achieve higher baud rates and allow all three to be
used for other functions.
*fCORE refers to the output of the PLL as described in the “On-Chip PLL” section.
–58–
REV. A
ADuC834
BAUD RATE GENERATION USING TIMER 1 AND TIMER 2
Timer 1 Generated Baud Rates
Timer 2 Generated Baud Rates
Baud rates can also be generated using Timer 2. Using Timer 2
is similar to using Timer 1 in that the timer must overflow 16
times before a bit is transmitted/received. Because Timer 2 has
a 16-bit Autoreload Mode, a wider range of baud rates is possible using Timer 2.
When Timer 1 is used as the baud rate generator, the baud rates
in Modes 1 and 3 are determined by the Timer 1 overflow rate
and the value of SMOD as follows:
(
)
Modes 1 and 3 Baud Rate = 2SMOD ⁄ 32 × (Timer 1 Overflow Rate)
Mode 1 and Mode 3 Baud Rate = (1 16) × (Timer 2 Overflow Rate)
The Timer 1 interrupt should be disabled in this application.
The timer itself can be configured for either timer or counter
operation, and in any of its three running modes. In the most
typical application, it is configured for timer operation, in the
Autoreload Mode (high nibble of TMOD = 0100 binary). In
that case, the baud rate is given by the formula:
Mode 1 and Mode 3 Baud Rate =
Therefore when Timer 2 is used to generate baud rates, the
timer increments every two clock cycles and not every core
machine cycle as before. Thus, it increments six times faster
than Timer 1, and therefore baud rates six times faster are possible. Because Timer 2 has a 16-bit autoreload capability, very
low baud rates are still possible.
2SMOD × fCORE
32 × 12 (256 − TH1)
Timer 2 is selected as the baud rate generator by setting the
TCLK and/or RCLK in T2CON. The baud rates for transmit
and receive can be simultaneously different. Setting RCLK and/or
TCLK puts Timer 2 into its baud rate generator mode as shown
in Figure 56. In this case, the baud rate is given by the formula:
A very low baud rate can also be achieved with Timer 1 by
leaving the Timer 1 interrupt enabled, configuring the timer to
run as a 16-bit timer (high nibble of TMOD = 0100 binary), and
using the Timer 1 interrupt to do a 16-bit software reload.
Table XXXI shows some commonly-used baud rates and how
they might be calculated from a core clock frequency of 1.5728
MHz and 12.58 MHz using Timer 1. Generally speaking, a 5%
error is tolerable using asynchronous (start/stop) communications.
Mode 1 and Mode 3 Baud Rate =
fCORE
32 × (65536 − RCAP2H L)
Table XXXII shows some commonly used baud rates and
how they might be calculated from a core clock frequency of
1.5728 MHz and 12.5829 MHz using Timer 2.
Table XXXI. Commonly Used Baud Rates, Timer 1
Ideal
Baud
Core
CLK
SMOD
Value
TH1-Reload
Value
Actual
Baud
%
Error
9600
1600
1200
1200
12.58
12.58
12.58
1.57
1
1
1
1
–7 (F9H)
–27 (E5H)
–55 (C9H)
–7 (F9H)
9362
1627
1192
1170
2.5
1.1
0.7
2.5
Table XXXII. Commonly Used Baud Rates, Timer 2
Ideal
Baud
Core
CLK
RCAP2H
Value
RCAP2L
Value
Actual
Baud
%
Error
19200
9600
1600
1200
9600
1600
1200
12.58
12.58
12.58
12.58
1.57
1.57
1.57
–1 (FFH)
–1 (FFH)
–1 (FFH)
–2 (FEH)
–1 (FFH)
–1 (FFH)
–1 (FFH)
–20 (ECH)
–41 (D7H)
–164 (5CH)
–72 (B8H)
–5 (FBH)
–20 (ECH)
–41 (D7H)
19661
9591
2398
1199
9830
1658
1199
2.4
0.1
0.1
0.1
2.4
2.4
0.1
TIMER 1
OVERFLOW
2
OSC. FREQ. IS DIVIDED BY 2, NOT 12.
0
CORE
CLK*
2
SMOD
C/ T2 = 0
TL2
(8 BITS)
T2
PIN
TH2
(8 BITS)
TIMER 2
OVERFLOW
1
RCLK
16
1
0
RELOAD
16
RCAP2L
T2EX
PIN
RX
CLOCK
TCLK
NOTE AVAILABILITY OF ADDITIONAL
EXTERNAL INTERRUPT
EXF 2
RCAP2H
TIMER 2
INTERRUPT
CONTROL
EXEN2
*THE CORE CLOCK IS THE OUTPUT OF THE PLL (SEE "ON-CHIP PLL")
Figure 56. Timer 2, UART Baud Rates
REV. A
0
C/ T2 = 1
TR2
TRANSITION
DETECTOR
1
CONTROL
–59–
TX
CLOCK
ADuC834
BAUD RATE GENERATION USING TIMER 3
The high integer dividers in a UART block means that high
speed baud rates are not always possible using some particular
crystals. e.g., using a 12 MHz crystal, a baud rate of 115200 is
not possible. To address this problem the ADuC834 has added
a dedicated baud rate timer (Timer 3) specifically for generating
highly accurate baud rates.
Timer 3 can be used instead of Timer 1 or Timer 2 for generating
very accurate high speed UART baud rates including 115200
and 230400. Timer 3 also allows a much wider range of baud
rates to be obtained. In fact, every desired bit rate from 12 bits
to 393216 bits can be generated to within an error of ± 0.8%.
Timer 3 also frees up the other three timers allowing them to be
used for different applications. A block diagram of Timer 3 is
shown in Figure 57.
CORE
CLK*
2
(1 + T3FD/64)
Note: The DIV value must be rounded down.


fCORE
log 

 32 × Baud Rate 
DIV =
log (2)
T3FD is the fractional divider ratio required to achieve the
required baud rate. We can calculate the appropriate value for
T3FD using the following formula.
Note: T3FD should be rounded to the nearest integer.
T 3FD =
TIMER 1/TIMER 2
RX CLOCK (FIG 56)
1
Actual Baud Rate =
0
2DIV
1
16
T3 RX/TX
CLOCK
2 × fCORE
2 DIV × Baud Rate
RX
CLOCK
0
− 64
Once the values for DIV and T3FD are calculated, the actual
baud rate can be calculated using the following formula:
TIMER 1/TIMER 2
TX CLOCK (FIG 56)
FRACTIONAL
DIVIDER
The appropriate value to write to the DIV2-1-0 bits can be
calculated using the following formula where fCORE is the output
of the PLL as described in the “On-Chip PLL” description.
DIV = log (12582912/32 × 115200) / log 2 = 1.77 = 1
(
)
T 3FD = (2 × 12.582912) 21 × 115200 − 64 = 45.22 = 2Dh
TX CLOCK
*THE CORE CLOCK IS THE OUTPUT OF THE PLL (SEE "ON-CHIP PLL")
Two SFRs (T3CON and T3FD) are used to control Timer 3.
T3CON is the baud rate control SFR, allowing Timer 3 to be
used to set up the UART baud rate, and setting up the binary
divider (DIV).
2 × fCORE
× (T 3FD + 64)
For a baud rate of 115200 while operating from the maximum
core frequency (CD = 0) we have:
T3EN
Figure 57. Timer 3, UART Baud Rates
2
DIV
Therefore, the actual baud rate is 115439 bits.
Table XXXIV. Commonly Used Baud Rates Using Timer 3
Ideal
Baud
CD
DIV
T3CON
T3FD
%
Error
230400
0
0
80H
2DH
0.2
115200
115200
0
1
1
0
81H
80H
2DH
2DH
0.2
0.2
57600
57600
57600
0
1
2
2
1
0
82H
81H
80H
2DH
2DH
2DH
0.2
0.2
0.2
38400
38400
38400
38400
0
1
2
3
3
2
1
0
83H
82H
81H
80H
12H
12H
12H
12H
0.1
0.1
0.1
0.1
19200
19200
19200
19200
19200
0
1
2
3
4
4
3
2
1
0
84H
83H
82H
81H
80H
12H
12H
12H
12H
12H
0.1
0.1
0.1
0.1
0.1
9600
9600
9600
9600
9600
9600
38400
0
1
2
3
4
5
0
5
4
3
2
1
0
3
85H
84H
83H
82H
81H
80H
83H
12H
12H
12H
12H
12H
12H
12H
0.1
0.1
0.1
0.1
0.1
0.1
0.1
Table XXXIII. T3CON SFR Bit Designations
Bit
Name
Description
7
T3EN
Set to enable Timer 3 to generate the baud
rate. When set PCON.7, T2CON.4 and
T2CON.5 are ignored. Cleared to let the baud
rate be generated as per a standard 8052.
Reserved for future use
Reserved for future use
Reserved for future use
Reserved for future use
Binary Divider Factor
DIV2
DIV1 DIV0 Bin Divider
0
0
0
1
0
0
1
2
0
1
0
4
0
1
1
8
1
0
0
16
1
0
1
32
1
1
0
64
1
1
1
128
6
5
4
3
2
1
0
–––
–––
–––
–––
DIV2
DIV1
DIV0
–60–
REV. A
ADuC834
INTERRUPT SYSTEM
The ADuC834 provides a total of 11 interrupt sources with two priority levels. The control and configuration of the interrupt system
is carried out through three interrupt-related SFRs. These are the IE (Interrupt Enable) Register, the IP (Interrupt Priority Register)
and the IEIP2 (Secondary Interrupt Enable/Priority SFR) Registers. Their bit definitions are given in the Tables XXXV – XXXVII.
IE
Interrupt Enable Register
SFR Address
Power-On Default Value
Bit Addressable
A8H
00H
Yes
Table XXXV. IE SFR Bit Designations
Bit
Name
Description
7
6
5
4
3
2
1
0
EA
EADC
ET2
ES
ET1
EX1
ET0
EX0
Written by User to Enable ‘1’ or Disable ‘0’ All Interrupt Sources
Written by User to Enable ‘1’ or Disable ‘0’ ADC Interrupt
Written by User to Enable ‘1’ or Disable ‘0’ Timer 2 Interrupt
Written by User to Enable ‘1’ or Disable ‘0’ UART Serial Port Interrupt
Written by User to Enable ‘1’ or Disable ‘0’ Timer 1 Interrupt
Written by User to Enable ‘1’ or Disable ‘0’ External Interrupt 1
Written by User to Enable ‘1’ or Disable ‘0’ Timer 0 Interrupt
Written by User to Enable ‘1’ or Disable ‘0’ External Interrupt 0
IP
Interrupt Priority Register
SFR Address
Power-On Default Value
Bit Addressable
B8H
00H
Yes
Table XXXVI. IP SFR Bit Designations
Bit
Name
Description
7
6
5
4
3
2
1
0
–––
PADC
PT2
PS
PT1
PX1
PT0
PX0
Reserved for Future Use
Written by User to Select ADC Interrupt Priority (‘1’ = High; ‘0’ = Low)
Written by User to Select Timer 2 Interrupt Priority (‘1’ = High; ‘0’ = Low)
Written by User to Select UART Serial Port Interrupt Priority (‘1’ = High; ‘0’ = Low)
Written by User to Select Timer 1 Interrupt Priority (‘1’ = High; ‘0’ = Low)
Written by User to Select External Interrupt 1 Priority (‘1’ = High; ‘0’ = Low)
Written by User to Select Timer 0 Interrupt Priority (‘1’ = High; ‘0’ = Low)
Written by User to Select External Interrupt 0 Priority (‘1’ = High; ‘0’ = Low)
IEIP2
Secondary Interrupt Enable and Priority Register
SFR Address
Power-On Default Value
Bit Addressable
A9H
A0H
No
Table XXXVII. IEIP2 SFR Bit Designations
Bit
Name
Description
7
6
5
4
3
2
1
0
–––
PTI
PPSM
PSI
–––
ETI
EPSM
ESI
Reserved for Future Use
Written by User to Select TIC Interrupt Priority (‘1’ = High; ‘0’ = Low)
Written by User to Select Power Supply Monitor Interrupt Priority (‘1’ = High; ‘0’ = Low)
Written by User to Select SPI/I2C Serial Port Interrupt Priority (‘1’ = High; ‘0’ = Low)
Reserved. This Bit Must Be ‘0.’
Written by User to Enable ‘1’ or Disable ‘0’ TIC Interrupt
Written by User to Enable ‘1’ or Disable ‘0’ Power Supply Monitor Interrupt
Written by User to Enable ‘1’ or Disable ‘0’ SPI/I2C Serial Port Interrupt
REV. A
–61–
ADuC834
Interrupt Priority
Interrupt Vectors
The Interrupt Enable registers are written by the user to enable
individual interrupt sources, while the Interrupt Priority registers
allow the user to select one of two priority levels for each interrupt. An interrupt of a high priority may interrupt the service
routine of a low priority interrupt, and if two interrupts of different
priority occur at the same time, the higher level interrupt will be
serviced first. An interrupt cannot be interrupted by another
interrupt of the same priority level. If two interrupts of the same
priority level occur simultaneously, a polling sequence is used to
determine which interrupt is serviced first. The polling sequence
is shown in Table XXXVIII.
When an interrupt occurs, the program counter is pushed onto
the stack and the corresponding interrupt vector address is
loaded into the program counter. The interrupt vector addresses
are shown in Table XXXIX.
Table XXXVIII. Priority within an Interrupt Level
Source
Priority
Description
PSMI
WDS
IE0
RDY0/RDY1
TF0
IE1
TF1
ISPI/I2CI
RI + TI
TF2 + EXF2
TII
1 (Highest)
2
3
4
5
6
7
8
9
10
11 (Lowest)
Power Supply Monitor Interrupt
Watchdog Interrupt
External Interrupt 0
ADC Interrupt
Timer/Counter 0 Interrupt
External Interrupt 1
Timer/Counter 1 Interrupt
SPI Interrupt
Serial Interrupt
Timer/Counter 2 Interrupt
Time Interval Counter Interrupt
Table XXXIX. Interrupt Vector Addresses
Source
Vector Address
IE0
TF0
IE1
TF1
RI + TI
TF2 + EXF2
RDY0/RDY1 (ADC)
ISPI/I2CI
PSMI
TII
WDS (WDIR = 1)*
0003H
000BH
0013H
001BH
0023H
002BH
0033H
003BH
0043H
0053H
005BH
*The watchdog can be configured to generate an interrupt instead of a reset
when it times out. This is used for logging errors or to examine the internal
status of the microcontroller core to understand, from a software debug point
of view, why a watchdog timeout occurred. The watchdog interrupt is slightly
different from the normal interrupts in that its priority level is always set to 1
and it is not possible to disable the interrupt via the global disable bit ( EA) in
the IE SFR. This is done to ensure that the interrupt will always be responded
to if a watchdog timeout occurs. The watchdog will only produce an interrupt
if the watchdog timeout is greater than zero.
–62–
REV. A
ADuC834
Though both external program memory and external data
memory are accessed using some of the same pins, the two are
completely independent of each other from a software point of
view. For example, the chip can read/write external data memory
while executing from external program memory.
ADuC834 HARDWARE DESIGN CONSIDERATIONS
This section outlines some of the key hardware design considerations that must be addressed when integrating the ADuC834
into any hardware system.
External Memory Interface
Figure 59 shows a hardware configuration for accessing up to
64 Kbytes of external data memory. This interface is standard
to any 8051 compatible MCU.
In addition to its internal program and data memories, the
ADuC834 can access up to 64 Kbytes of external program memory
(ROM/PROM/and so on) and up to 16 Mbytes of external data
memory (SRAM).
D0–D7
(DATA)
P0
LATCH
A0–A7
ALE
A8–A15
P2
Note that a second very important function of the EA pin is
described in the Single Pin Emulation Mode section.
External program memory (if used) must be connected to
the ADuC834 as illustrated in Figure 58. Sixteen I/O lines
(Ports 0 and 2) are dedicated to bus functions during external
program memory fetches. Port 0 (P0) serves as a multiplexed
address/databus. It emits the low byte of the program counter
(PCL) as an address, and then goes into a high impedance input
state awaiting the arrival of the code byte from the program
memory. During the time that the low byte of the program counter
is valid on P0, the signal ALE (Address Latch Enable) clocks
this byte into an external address latch. Meanwhile, Port 2 (P2)
emits the high byte of the program counter (PCH), and PSEN
strobes the EPROM and the code byte is read into the ADuC834.
SRAM
ADuC834
To select from which code space (internal or external program
memory) to begin executing code, tie the EA (external access)
pin high or low, respectively. When EA is high (pulled up to
VDD), user program execution will start at Address 0 in the
internal 62 Kbytes Flash/EE code space. When EA is low (tied
to ground) user program execution will start at Address 0 in the
external code space. When executing from internal code space,
accesses to the program space above F7FFH (62 Kbytes) will be
read as NOP instructions.
RD
OE
WR
WE
Figure 59. External Data Memory Interface
(64 Kbytes Address Space)
If access to more than 64 Kbytes of RAM is desired, a feature
unique to the MicroConverter allows addressing up to 16 Mbytes
of external RAM simply by adding an additional latch as illustrated in Figure 60.
SRAM
ADuC834
D0–D7
(DATA)
P0
LATCH
A0–A7
ALE
ADuC834
EPROM
A8–A15
P2
D0–D7
(INSTRUCTION)
P0
LATCH
LATCH
A16–A23
A0–A7
ALE
P2
PSEN
RD
OE
WR
WE
A8–A15
Figure 60. External Data Memory Interface
(16 Mbytes Address Space)
OE
Figure 58. External Program Memory Interface
Note that program memory addresses are always 16 bits wide,
even in cases where the actual amount of program memory used
is less than 64 Kbytes. External program execution sacrifices two
of the 8-bit ports (P0 and P2) to the function of addressing the
program memory. While executing from external program memory,
Ports 0 and 2 can be used simultaneously for read/write access
to external data memory, but not for general-purpose I/O.
In either implementation, Port 0 (P0) serves as a multiplexed
address/databus. It emits the low byte of the data pointer (DPL)
as an address, which is latched by ALE prior to data being placed
on the bus by the ADuC834 (write operation) or the external
data memory (read operation). Port 2 (P2) provides the data
pointer page byte (DPP) to be latched by ALE, followed by the
data pointer high byte (DPH). If no latch is connected to P2,
DPP is ignored by the SRAM, and the 8051 standard of 64 Kbyte
external data memory access is maintained.
Detailed timing diagrams of external program and data memory
read and write access can be found in the Timing Specification
sections of this data sheet.
REV. A
–63–
ADuC834
Power Supplies
The ADuC834’s operational power supply voltage range is
2.7 V to 5.25 V. Although the guaranteed data sheet specifications are given only for power supplies within 2.7 V to 3.6 V or
5% of the nominal 5 V level, the chip will function equally well
at any power supply level between 2.7 V and 5.25 V.
Separate analog and digital power supply pins (AVDD and DVDD
respectively) allow AVDD to be kept relatively free of noisy digital signals often present on the system DVDD line. In this mode,
the part can also operate with split supplies; that is, using different voltage supply levels for each supply. For example, this
means that the system can be designed to operate with a DVDD
voltage level of 3 V while the AVDD level can be at 5 V, or viceversa if required. A typical split supply configuration is shown in
Figure 61.
ANALOG SUPPLY
DIGITAL SUPPLY
10F
10F
+
–
+
–
ADuC834
20
34 DVDD
AVDD
5
Notice that in both Figure 61 and Figure 62 a large value (10 F)
reservoir capacitor sits on DVDD and a separate 10 F capacitor
sits on AVDD. Also, local decoupling capacitors (0.1 F) are
located at each VDD pin of the chip. As per standard design
practice, be sure to include all of these capacitors and ensure
the smaller capacitors are closest to each VDD pin with lead
lengths as short as possible. Connect the ground terminal of
each of these capacitors directly to the underlying ground plane.
Finally, it should also be noticed that, at all times, the analog
and digital ground pins on the ADuC834 should be referenced
to the same system ground reference point.
Power-On Reset Operation
An internal POR (Power-On Reset) is implemented on the
ADuC834. For DVDD below 2.45 V, the internal POR will hold
the ADuC834 in reset. As DVDD rises above 2.45 V, an internal
timer will time out for typically 128 ms before the part is
released from reset. The user must ensure that the power supply
has reached a stable 2.7 V minimum level by this time. Likewise
on power-down, the internal POR will hold the ADuC834 in
reset until the power supply has dropped below 1 V. Figure 63
illustrates the operation of the internal POR in detail.
0.1F
48
0.1F
2.45V TYP
DVDD
21
35 DGND
AGND
1.0V TYP
6
128ms TYP
128ms TYP
1.0V TYP
47
INTERNAL
CORE RESET
Figure 61. External Dual Supply Connections
As an alternative to providing two separate power supplies,
AVDD can be kept quiet by placing a small series resistor and/or
ferrite bead between it and DVDD, and then decoupling AVDD
separately to ground. An example of this configuration is shown
in Figure 62. In this configuration, other analog circuitry (such
as op amps, voltage reference, and so on) can be powered from
the AVDD supply line as well.
DIGITAL SUPPLY
+
–
10F
BEAD
1.6
10F
ADuC834
20
34 DVDD
AVDD
5
0.1F
48
0.1F
21
35 DGND
47
AGND
Figure 63. Internal Power-on-Reset Operation
Power Consumption
The DVDD power supply current consumption is specified in
normal, idle, and power-down modes. The AVDD power supply
current is specified with the analog peripherals disabled. The
normal mode power consumption represents the current drawn
from DVDD by the digital core. The other on-chip peripherals
(watchdog timer, power supply monitor, and so on) consume
negligible current and are therefore lumped in with the normal
operating current here. Of course, the user must add any currents sourced by the parallel and serial I/O pins, and those
sourced by the DAC in order to determine the total current
needed at the ADuC834’s DVDD and AVDD supply pins. Also,
current drawn from the DVDD supply will increase by approximately 5 mA during Flash/EE erase and program cycles.
6
Figure 62. External Single Supply Connections
–64–
REV. A
ADuC834
Power Saving Modes
Wake-Up from Power-Down Latency
Setting the Idle and Power-Down Mode Bits, PCON.0 and
PCON.1 respectively, in the PCON SFR described in Table II
allows the chip to be switched from Normal mode into Idle
mode, and also into full Power-Down mode.
Even with the 32 kHz crystal enabled during power-down, the
PLL will take some time to lock after a wake-up from powerdown. Typically, the PLL will take about 1 ms to lock. During
this time, code will execute but not at the specified frequency.
Some operations require an accurate clock, for example UART
communications, to achieve specified 50/60 Hz rejection from
the ADCs. The following code may be used to wait for the PLL
to lock:
In Idle mode, the oscillator continues to run, but the core clock
generated from the PLL is halted. The on-chip peripherals
continue to receive the clock and remain functional. The CPU
status is preserved with the stack pointer, program counter, and
all other internal registers maintain their data during Idle mode.
Port pins and DAC output pins also retain their states, and ALE
and PSEN outputs go high in this mode. The chip will recover
from Idle mode upon receiving any enabled interrupt, or on
receiving a hardware reset.
In Power-Down mode, both the PLL and the clock to the core are
stopped. The on-chip oscillator can be halted or can continue to
oscillate, depending on the state of the oscillator power-down
bit (OSC_PD) in the PLLCON SFR. The TIC, being driven
directly from the oscillator, can also be enabled during powerdown. All other on-chip peripherals however, are shut down. Port
pins retain their logic levels in this mode, but the DAC output
goes to a high impedance state (three-state) while ALE and PSEN
outputs are held low. During full Power-Down mode with the
oscillator and wake-up timer running, the ADuC834 typically
consumes a total of 15 A. There are five ways of terminating
Power-Down mode:
Asserting the RESET Pin (Pin 15)
Returns to Normal Mode. All registers are set to their reset
default value and program execution starts at the reset vector
once the RESET pin is deasserted.
Cycling Power
All registers are set to their default state and program execution
starts at the reset vector approximately 128 ms later.
Time Interval Counter (TIC) Interrupt
If the OSC_PD bit in the PLLCON SFR is clear, the 32 kHz
oscillator will remain powered up even in Power-Down mode. If
the Time Interval Counter (Wakeup/RTC timer) is enabled,
a TIC interrupt will wake the ADuC834 up from Power-Down
mode. The CPU services the TIC interrupt. The RETI at the
end of the TIC ISR will return the core to the instruction after
that which enabled power-down.
SPI Interrupt
If the SERIPD Bit in the PCON SFR is set, then an SPI interrupt, if enabled, will wake the ADuC834 up from Power-Down
mode. The CPU services the SPI interrupt. The RETI at the
end of the ISR will return the core to the instruction after that
which enabled power-down.
INT0 Interrupt
If the INT0PD bit in the PCON SFR is set, an external
interrupt 0, if enabled, will wake up the ADuC834 from powerdown. The CPU services the SPI interrupt. The RETI at the end
of the ISR will return the core to the instruction after that which
enabled power-down.
REV. A
WAITFORLOCK:
MOV
A, PLLCON
JNB
ACC.6, WAITFORLOCK
If the crystal has been powered down during power-down, there
is an additional delay associated with the startup of the crystal
oscillator before the PLL can lock. 32 kHz crystals are inherently
slow to oscillate, typically taking about 150 ms. Once again, during
this time before lock, code will execute but the exact frequency
of the clock cannot be guaranteed. Again for any timing sensitive
operations, it is recommended to wait for lock using the lock bit
in PLLCON as shown above.
Grounding and Board Layout Recommendations
As with all high resolution data converters, special attention must
be paid to grounding and PC board layout of ADuC834-based
designs in order to achieve optimum performance from the
ADCs and DAC.
Although the ADuC834 has separate pins for analog and digital
ground (AGND and DGND), the user must not tie these to two
separate ground planes unless the two ground planes are connected together very close to the ADuC834, as illustrated in the
simplified example of Figure 64a. In systems where digital and
analog ground planes are connected together somewhere else
(at the system’s power supply for example), they cannot be
connected again near the ADuC834 since a ground loop would
result. In these cases, tie the ADuC834’s AGND and DGND
Pins all to the analog ground plane, as illustrated in Figure 64b.
In systems with only one ground plane, ensure that the digital
and analog components are physically separated onto separate
halves of the board such that digital return currents do not flow
near analog circuitry and vice versa. The ADuC834 can then be
placed between the digital and analog sections, as illustrated in
Figure 64c.
In all of these scenarios, and in more complicated real-life applications, keep in mind the flow of current from the supplies and
back to ground. Make sure the return paths for all currents are
as close as possible to the paths the currents took to reach their
destinations. For example, do not power components on the
analog side of Figure 64b with DVDD since that would force return
currents from DVDD to flow through AGND. Also, try to avoid
digital currents flowing under analog circuitry, which could happen
if the user placed a noisy digital chip on the left half of the board
in Figure 64c. Whenever possible, avoid large discontinuities in
the ground plane(s) (such as are formed by a long trace on the
same layer), since they force return signals to travel a longer path.
And of course, make all connections to the ground plane directly,
with little or no trace separating the pin from its via to ground.
–65–
ADuC834
a.
PLACE ANALOG
COMPONENTS
HERE
The CHIPID SFR is a read-only register located at SFR
address C2H. The upper nibble of this SFR designates the
MicroConverter within the Σ-∆ ADC family. User software can
read this SFR to identify the host MicroConverter and thus
execute slightly different code if required. The CHIPID SFR reads
as follows for the Σ-∆ ADC family of MicroConverter products.
PLACE DIGITAL
COMPONENTS
HERE
AGND
DGND
ADuC836
ADuC834
ADuC824
ADuC816
b.
PLACE ANALOG
COMPONENTS
HERE
c.
Clock Oscillator
PLACE DIGITAL
COMPONENTS
HERE
AGND
As described earlier, the core clock frequency for the ADuC834
is generated from an on-chip PLL that locks onto a multiple
(384 times) of 32.768 kHz. The latter is generated from an
internal clock oscillator. To use the internal clock oscillator,
connect a 32.768 kHz parallel resonant crystal between XTAL1
and XTAL2 pins (32 and 33) as shown in Figure 65.
DGND
PLACE ANALOG
COMPONENTS
HERE
CHIPID = 3xH
CHIPID = 2xH
CHIPID = 0xH
CHIPID = 1xH
PLACE DIGITAL
COMPONENTS
HERE
GND
Figure 64. System Grounding Schemes
If the user plans to connect fast logic signals (rise/fall time < 5 ns)
to any of the ADuC834’s digital inputs, add a series resistor to
each relevant line to keep rise and fall times longer than 5 ns at
the ADuC834 input pins. A value of 100 Ω or 200 Ω is usually
sufficient to prevent high speed signals from coupling capacitively into the ADuC834 and affecting the accuracy of ADC
conversions.
As shown in the typical external crystal connection diagram in
Figure 65, two internal 12 pF capacitors are provided on-chip.
These are connected internally, directly to the XTAL1 and
XTAL2 pins, and the total input capacitances at both pins is
detailed in the Specification section of this data sheet. The value
of the total load capacitance required for the external crystal
should be the value recommended by the crystal manufacturer
for use with that specific crystal. In many cases, because of the
on-chip capacitors, additional external load capacitors will not
be required.
ADuC834
XTAL1
32
12pF
32.768kHz
ADuC834 System Self-Identification
In some hardware designs, it may be an advantage for the
software running on the ADuC834 target to identify the host
MicroConverter. For example, code running on the ADuC834
may also be used with the ADuC824 or the ADuC816, and is
required to operate differently.
33
XTAL2
12pF
TO INTERNAL
PLL
Figure 65. External Parallel Resonant Crystal
Connections Other Hardware Considerations
To facilitate in-circuit programming, plus in-circuit debug and
emulation options, users will want to implement some simple
connection points in their hardware that will allow easy access
to Download, Debug, and Emulation modes.
–66–
REV. A
ADuC834
OTHER HARDWARE CONSIDERATIONS
In-Circuit Serial Download Access
Embedded Serial Port Debugger
Nearly all ADuC834 designs will want to take advantage of the
in-circuit reprogrammability of the chip. This is accomplished
by a connection to the ADuC834’s UART, which requires an
external RS-232 chip for level translation if downloading code
from a PC. Basic configuration of an RS-232 connection is
illustrated in Figure 66 with a simple ADM3202-based circuit.
If users would rather not include an RS-232 chip onto the target
board, refer to the application note uC006–A 4-Wire UART-to-PC
Interface available at www.analog.com/microconverter, for a
simple (and zero-cost-per-board) method of gaining in-circuit
serial download access to the ADuC834.
In addition to the basic UART connections, users will also need
a way to trigger the chip into Download mode. This is accomplished via a 1 kΩ pull-down resistor that can be jumpered onto
the PSEN pin, as shown in Figure 66. To get the ADuC834 into
Download mode, simply connect this jumper and power-cycle
the device (or manually reset the device, if a manual reset button
is available) and it will be ready to receive a new program serially.
With the jumper removed, the device will power-on in Normal
mode (and run the program) whenever power is cycled or RESET
is toggled.
Note that PSEN is normally an output (as described in the
External Memory Interface section) and it is sampled as an input
only on the falling edge of RESET (i.e., at power-up or upon an
external manual reset). Note also that if any external circuitry
unintentionally pulls PSEN low during power-up or reset events,
it could cause the chip to enter Download Mode and therefore
fail to begin user code execution as it should. To prevent this,
ensure that no external signals are capable of pulling the PSEN
pin low, except for the external PSEN jumper itself.
REV. A
From a hardware perspective, entry to Serial Port Debug mode
is identical to the serial download entry sequence described
above. In fact, both Serial Download and Serial Port Debug
modes can be thought of as essentially one mode of operation
used in two different ways.
Note that the serial port debugger is fully contained on the
ADuC834 device, (unlike “ROM monitor” type debuggers) and
therefore no external memory is needed to enable in-system
debug sessions.
Single-Pin Emulation Mode
Also built into the ADuC834 is a dedicated controller for singlepin in-circuit emulation (ICE) using standard production ADuC834
devices. In this mode, emulation access is gained by connection
to a single pin, the EA pin. Normally, this pin is hard-wired
either high or low to select execution from internal or external
program memory space, as described earlier. To enable single-pin
emulation mode, however, users will need to pull the EA pin
high through a 1 kΩ resistor as shown in Figure 66. The emulator
will then connect to the 2-pin header also shown in Figure 66.
To be compatible with the standard connector that comes
with the single-pin emulator available from Accutron Limited
(www.accutron.com), use a 2-pin 0.1-inch pitch Friction Lock
header from Molex (www.molex.com) such as their part number
22-27-2021. Be sure to observe the polarity of this header. As
represented in Figure 66, when the Friction Lock tab is at the
right, the ground pin should be the lower of the two pins (when
viewed from the top).
–67–
ADuC834
resistance. This differential voltage is routed directly to the positive
and negative inputs of the primary ADC (AIN1, AIN2 respectively). The same current that excited the RTD also flows through
a series resistance RREF generating a ratiometric voltage reference
VREF. The ratiometric voltage reference ensures that variations
in the excitation current do not affect the measurement system as
the input voltage from the RTD and reference voltage across
RREF vary ratiometrically with the excitation current. Resistor
RREF must, however, have a low temperature coefficient to avoid
errors in the reference voltage over temperature. RREF must
also be large enough to generate at least a 1 V voltage reference.
Typical System Configuration
A typical ADuC834 configuration is shown in Figure 66. It
summarizes some of the hardware considerations discussed in
the previous paragraphs.
Figure 66 also includes connections for a typical analog measurement application of the ADuC834, namely an interface to an
RTD (Resistive Temperature Device). The arrangement shown
is commonly referred to as a 4-wire RTD configuration.
Here, the on-chip excitation current sources are enabled to excite
the sensor. The excitation current flows directly through the
RTD generating a voltage across the RTD proportional to its
DOWNLOAD/DEBUG
ENABLE JUMPER
(NORMALLY OPEN)
DVDD
1k
DVDD
200A/400A
EXCITATION
CURRENT
AVDD
49
48
47
46
45
44
43
42
2-PIN HEADER FOR
EMULATION ACCESS
(NORMALLY OPEN)
39
P1.2/IEXC1/DAC
37
P1.3/AIN5/DAC
36
DVDD
DGND 35
AGND
RREF
5.6k
40
38
AVDD
RTD
41
EA
50
PSEN
51
DVDD
52
DGND
1k
DVDD 34
ADuC834
REFIN–
XTAL2 33
REFIN+
XTAL1 32
P1.4/AIN1
31
P1.5/AIN2
30
32.768kHz
DGND
DVDD
TXD
RXD
RESET
29
28
27
NOT CONNECTED IN THIS EXAMPLE
DVDD
DVDD
ALL CAPACITORS IN THIS EXAMPLE ARE
0.1F CERAMIC CAPACITORS
RS-232 INTERFACE*
ADM3202
C1+
V+
VCC
STANDARD D-TYPE
SERIAL COMMS
CONNECTOR TO
PC HOST
GND
1
C1–
T1OUT
2
C2+
R1IN
3
C2–
R1OUT
4
V–
T1IN
5
T2OUT
T2IN
6
R2OUT
7
R2IN
8
9
*EXTERNAL UART TRANSCEIVER INTEGRATED IN SYSTEM OR AS
PART OF AN EXTERNAL DONGLE AS DESCRIBED IN uC006.
Figure 66. Typical System Configuration
–68–
REV. A
ADuC834
Hardware:
ADuC834 Evaluation Board,
and Serial Port Cable
Download—In Circuit Downloader
The Serial Downloader is a software program that allows the user
to serially download an assembled program (Intel Hex format
file) to the on-chip program FLASH memory via the serial COM1
port on a standard PC. An Application Note (uC004) detailing
this serial download protocol is available from www.analog.com/
microconverter.
Code Development:
8051 Assembler
Debugger/Emulator—In-Circuit Debugger/Emulator
Code Functionality:
ADSIM, Windows
MicroConverter Code
Simulator
In-Circuit Code Download:
Serial Downloader
QUICKSTART DEVELOPMENT SYSTEM
The QuickStart Development System is a full featured, low cost
development tool suite supporting the ADuC834. The system
consists of the following PC-based (Windows® compatible)
hardware and software development tools.
The Debugger/Emulator is a Windows application that allows the
user to debug code execution on silicon using the MicroConverter
UART serial port or via a single pin to provide non intrusive
debug. The debugger provides access to all on-chip peripherals
during a typical debug session, including single-step and multiple break-point code execution control. C source and assembly
level debug are both possible with the emulator.
In-Circuit Debugger/Emulator: Serial Port/Single Pin
Debugger/Emulator with
Assembly and C Source
debug
Miscellaneous Other:
ADSIM—Windows Simulator
CD-ROM Documentation
and Two Additional
Prototype Devices
Figures 67 shows the typical components of a QuickStart Development System while Figure 68 shows a typical debug session.
A brief description of some of the software tools’ components in
the QuickStart Development System is given below.
The Simulator is a Windows application that fully simulates the
MicroConverter functionality including ADC and DAC peripherals. The simulator provides an easy-to-use, intuitive, interface to
the MicroConverter functionality and integrates many standard
debug features, including multiple breakpoints, single stepping,
and code execution trace capability. This tool can be used both
as a tutorial guide to the part as well as an efficient way to prove
code functionality before moving to a hardware platform.
Figure 68. Typical Debug Session
Figure 67. Components of the QuickStart Development
System
REV. A
–69–
ADuC834
(AVDD = 2.7 V to 3.6 V or 4.75 V to 5.25 V, DVDD = 2.7 V to 3.6 V or 4.75 V to 5.25 V;
MIN to TMAX, unless otherwise noted.)
TIMING SPECIFICATIONS1, 2, 3 all specifications T
32.768 kHz External Crystal
Min
Typ
Max
Parameter
CLOCK INPUT (External Clock Driven XTAL1)
XTAL1 Period
tCK
tCKL
XTAL1 Width Low
XTAL1 Width High
tCKH
XTAL1 Rise Time
tCKR
tCKF
XTAL1 Fall Time
ADuC834 Core Clock Frequency4
1/tCORE
ADuC834 Core Clock Period5
tCORE
tCYC
ADuC834 Machine Cycle Time6
30.52
6.26
6.26
9
9
0.098
12.58
0.636
7.6
0.95
122.45
Unit
Figure
s
s
s
s
s
MHz
s
s
69
69
69
69
69
NOTES
1
AC inputs during testing are driven at DV DD – 0.5 V for a Logic 1, and 0.45 V for a Logic 0. Timing measurements are made at V IH min for a Logic 1, and V IL max
for a Logic 0 as shown in Figure 70.
2
For timing purposes, a port pin is no longer floating when a 100 mV change from load voltage occurs. A port pin begins to float when a 100 mV change from the
loaded VOH/VOL level occurs as shown in Figure 70.
3
CLOAD for Port0, ALE, PSEN outputs = 100 pF; C LOAD for all other outputs = 80 pF unless otherwise noted.
4
ADuC834 internal PLL locks onto a multiple (384 times) the external crystal frequency of 32.768 kHz to provide a stable 12.583 MHz internal clock for the system.
The core can operate at this frequency or at a binary submultiple called Core_Clk, selected via the PLLCON SFR.
5
This number is measured at the default Core_Clk operating frequency of 1.57 MHz.
6
ADuC834 Machine Cycle Time is nominally defined as 12/Core_Clk.
tCKR
tCKH
tCKL
tCKF
tCK
Figure 69. XTAL1 Input
DVDD – 0.5V
0.45V
0.2DVDD + 0.9V
TEST POINTS
0.2DVDD – 0.1V
VLOAD – 0.1V
VLOAD
VLOAD + 0.1V
TIMING
REFERENCE
POINTS
VLOAD – 0.1V
VLOAD
VLOAD + 0.1V
Figure 70. Timing Waveform Characteristics
–70–
REV. A
ADuC834
Parameter
EXTERNAL PROGRAM MEMORY
ALE Pulsewidth
tLHLL
Address Valid to ALE Low
tAVLL
tLLAX
Address Hold after ALE Low
ALE Low to Valid Instruction In
tLLIV
ALE Low to PSEN Low
tLLPL
tPLPH
PSEN Pulsewidth
PSEN Low to Valid Instruction In
tPLIV
Input Instruction Hold after PSEN
tPXIX
tPXIZ
Input Instruction Float after PSEN
Address to Valid Instruction In
tAVIV
PSEN Low to Address Float
tPLAZ
tPHAX
Address Hold after PSEN High
12.58 MHz Core_Clk
Min
Max
Variable Core_Clk
Min
Max
119
39
49
2tCORE – 40
tCORE – 40
tCORE – 30
218
4tCORE – 100
49
193
tCORE – 30
3tCORE – 45
133
3tCORE – 105
0
0
54
292
25
tCORE – 25
5tCORE – 105
25
0
0
CORE_CLK
tLHLL
ALE (O)
tAVLL
tPLPH
tLLPL
tLLIV
tPLIV
PSEN (O)
PORT 0 (I/O)
tPXIZ
tPLAZ
tLLAX
tPXIX
PCL
(OUT)
INSTRUCTION
(IN)
tAVIV
PORT 2 (O)
tPHAX
PCH
Figure 71. External Program Memory Read Cycle
REV. A
–71–
Unit
Figure
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
71
71
71
71
71
71
71
71
71
71
71
71
ADuC834
12.58 MHz Core_Clk
Min
Max
Parameter
EXTERNAL DATA MEMORY READ CYCLE
RD Pulsewidth
tRLRH
Address Valid after ALE Low
tAVLL
tLLAX
Address Hold after ALE Low
RD Low to Valid Data In
tRLDV
Data and Address Hold after RD
tRHDX
tRHDZ
Data Float after RD
ALE Low to Valid Data In
tLLDV
Address to Valid Data In
tAVDV
tLLWL
ALE Low to RD Low
Address Valid to RD Low
tAVWL
RD Low to Address Float
tRLAZ
tWHLH
RD High to ALE High
377
39
44
Variable Core_Clk
Min
Max
6tCORE – 100
tCORE – 40
tCORE – 35
232
0
5tCORE – 165
0
89
486
550
288
188
188
0
119
39
3tCORE – 50
4tCORE – 130
tCORE – 40
2tCORE – 70
8tCORE – 150
9tCORE – 165
3tCORE + 50
0
tCORE + 40
Unit
Figure
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
72
72
72
72
72
72
72
72
72
72
72
72
CORE_CLK
ALE (O)
tWHLH
PSEN (O)
tLLDV
tLLWL
tRLRH
RD (O)
tAVWL
tRLDV
tAVLL
tLLAX
tRHDX
tRHDZ
tRLAZ
PORT 0 (I/O)
A0–A7
(OUT)
DATA (IN)
tAVDV
PORT 2 (O)
A16–A23
A8–A15
Figure 72. External Data Memory Read Cycle
–72–
REV. A
ADuC834
Parameter
12.58 MHz Core_Clk
Min
Max
EXTERNAL DATA MEMORY WRITE CYCLE
tWLWH
WR Pulsewidth
Address Valid after ALE Low
tAVLL
Address Hold after ALE Low
tLLAX
ALE Low to WR Low
tLLWL
tAVWL
Address Valid to WR Low
Data Valid to WR Transition
tQVWX
Data Setup before WR
tQVWH
tWHQX
Data and Address Hold after WR
tWHLH
WR High to ALE High
377
39
44
188
188
29
406
29
39
288
119
Variable Core_Clk
Min
Max
6tCORE – 100
tCORE – 40
tCORE – 35
3tCORE – 50
4tCORE – 130
tCORE – 50
7tCORE – 150
tCORE – 50
tCORE – 40
3tCORE + 50
tCORE + 40
CORE_CLK
ALE (O)
tWHLH
PSEN (O)
tLLWL
tWLWH
WR (O)
tAVWL
tAVLL
tLLAX
PORT 0 (O)
A0–A7
PORT 2 (O)
A16–A23
tQVWX
tWHQX
tQVWH
DATA
A8–A15
Figure 73. External Data Memory Write Cycle
REV. A
–73–
Unit
Figure
ns
ns
ns
ns
ns
ns
ns
ns
ns
73
73
73
73
73
73
73
73
73
ADuC834
Parameter
12.58 MHz Core_Clk
Min
Typ
Max
UART TIMING (Shift Register Mode)
Serial Port Clock Cycle Time
tXLXL
Output Data Setup to Clock
tQVXH
tDVXH
Input Data Setup to Clock
Input Data Hold after Clock
tXHDX
tXHQX
Output Data Hold after Clock
662
292
0
42
Min
Variable Core_Clk
Typ
Max
0.95
12tCORE
10tCORE – 133
2tCORE + 133
0
2tCORE – 117
Unit
Figure
s
ns
ns
ns
ns
74
74
74
74
74
ALE (O)
tXLXL
TxD
(OUTPUT CLOCK)
67
01
SET RI
OR
SET TI
tQVXH
tXHQX
RxD
(OUTPUT DATA)
BIT 6
MSB
BIT 1
tDVXH
RxD
(INPUT DATA)
MSB
tXHDX
BIT 1
BIT 6
LSB
Figure 74. UART Timing in Shift Register Mode
–74–
REV. A
ADuC834
Parameter
Min
SPI MASTER MODE TIMING (CPHA = 1)
tSL
SCLOCK Low Pulsewidth*
tSH
SCLOCK High Pulsewidth*
Data Output Valid after SCLOCK Edge
tDAV
Data Input Setup Time before SCLOCK Edge
tDSU
Data Input Hold Time after SCLOCK Edge
tDHD
tDF
Data Output Fall Time
Data Output Rise Time
tDR
SCLOCK Rise Time
tSR
tSF
SCLOCK Fall Time
Typ
Max
630
630
50
100
100
10
10
10
10
25
25
25
25
Unit
Figure
ns
ns
ns
ns
ns
ns
ns
ns
ns
75
75
75
75
75
75
75
75
75
*Characterized under the following conditions:
Core clock divider bits CD2, CD1, and CD0 in PLLCON SFR set to 0, 1, and 1, respectively, i.e., core clock frequency = 1.57 MHz, and
SPI bit-rate selection bits SPR1 and SPR0 in SPICON SFR set to 0 and 0, respectively.
SCLOCK
(CPOL = 0)
tSH
tSL
tSF
tSR
SCLOCK
(CPOL = 1)
tDAV
tDOSU
tDF
tDR
MOSI
MSB
MISO
MSB IN
tDSU
BITS 6–1
BITS 6–1
LSB
LSB IN
tDHD
Figure 75. SPI Master Mode Timing (CPHA = 1)
REV. A
–75–
ADuC834
Parameter
Min
SPI MASTER MODE TIMING (CPHA = 0)
tSL
SCLOCK Low Pulsewidth*
tSH
SCLOCK High Pulsewidth*
Data Output Valid after SCLOCK Edge
tDAV
Data Output Setup before SCLOCK Edge
tDOSU
Data Input Setup Time before SCLOCK Edge
tDSU
tDHD
Data Input Hold Time after SCLOCK Edge
Data Output Fall Time
tDF
Data Output Rise Time
tDR
tSR
SCLOCK Rise Time
tSF
SCLOCK Fall Time
Typ
Max
630
630
50
150
100
100
10
10
10
10
25
25
25
25
Unit
Figure
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
76
76
76
76
76
76
76
76
76
76
*Characterized under the following conditions:
a. Core clock divider bits CD2, CD1 and CD0 in PLLCON SFR set to 0, 1, and 1 respectively, i.e., core clock frequency = 1.57 MHz, and
b. SPI bit-rate selection bits SPR1 and SPR0 in SPICON SFR set to 0 and 0 respectively.
SCLOCK
(CPOL = 0)
tSH
tSL
tSR
SCLOCK
(CPOL = 1)
tDAV
tDF
tSF
tDR
MOSI
BITS 6–1
MSB
MISO
BITS 6–1
MSB IN
tDSU
LSB
LSB IN
tDHD
Figure 76. SPI Master Mode Timing (CPHA = 0)
–76–
REV. A
ADuC834
Parameter
Min
SPI SLAVE MODE TIMING (CPHA = 1)
tSS
SS to SCLOCK Edge
tSL
SCLOCK Low Pulsewidth
SCLOCK High Pulsewidth
tSH
Data Output Valid after SCLOCK Edge
tDAV
Data Input Setup Time before SCLOCK Edge
tDSU
tDHD
Data Input Hold Time after SCLOCK Edge
Data Output Fall Time
tDF
Data Output Rise Time
tDR
tSR
SCLOCK Rise Time
SCLOCK Fall Time
tSF
tSFS
SS High after SCLOCK Edge
Typ
Max
0
330
330
50
100
100
10
10
10
10
25
25
25
25
0
SS
tSFS
tSS
SCLOCK
(CPOL = 0)
tSL
tSH
tSR
tSF
SCLOCK
(CPOL = 1)
tDAV
tDF
MISO
MOSI
BITS 6–1
MSB
BITS 6–1
MSB IN
tDSU
tDR
tDHD
Figure 77. SPI Slave Mode Timing (CPHA = 1)
REV. A
–77–
LSB
LSB IN
Unit
Figure
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
77
77
77
77
77
77
77
77
75
77
77
ADuC834
Parameter
Min
SPI SLAVE MODE TIMING (CPHA = 0)
SS to SCLOCK Edge
tSS
SCLOCK Low Pulsewidth
tSL
SCLOCK High Pulsewidth
tSH
tDAV
Data Output Valid after SCLOCK Edge
Data Input Setup Time before SCLOCK Edge
tDSU
Data Input Hold Time after SCLOCK Edge
tDHD
tDF
Data Output Fall Time
Data Output Rise Time
tDR
SCLOCK Rise Time
tSR
tSF
SCLOCK Fall Time
SS to SCLOCK Edge
tSSR
Data Output Valid after SS Edge
tDOSS
tSFS
SS High after SCLOCK Edge
Typ
Max
0
330
330
50
100
100
10
10
10
10
25
25
25
25
50
20
0
Unit
Figure
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
78
78
78
78
78
78
78
78
78
78
78
78
78
SS
tSFS
tSS
SCLOCK
(CPOL = 0)
tSH
tSL
tSF
tSR
SCLOCK
(CPOL = 1)
tDAV
tDOSS
tDF
MISO
MOSI
MSB
MSB IN
tDSU
tDR
BITS 6–1
BITS 6–1
LSB
LSB IN
tDHD
Figure 78. SPI Slave Mode Timing (CPHA = 0)
–78–
REV. A
ADuC834
Parameter
Min
Max
Unit
Figure
µs
µs
µs
ns
µs
µs
µs
µs
79
79
79
79
79
79
79
79
ns
ns
ns
79
79
79
2
I C-SERIAL INTERFACE TIMING
tL
SCLOCK Low Pulsewidth
SCLOCK High Pulsewidth
tH
Start Condition Hold Time
tSHD
tDSU
Data Setup Time
Data Hold Time
tDHD
Setup Time for Repeated Start
tRSU
tPSU
Stop Condition Setup Time
Bus Free Time between a STOP
tBUF
Condition and a START Condition
Rise Time of Both SCLOCK and SDATA
tR
Fall Time of Both SCLOCK and SDATA
tF
tSUP*
Pulsewidth of Spike Suppressed
4.7
4.0
0.6
100
0.9
0.6
0.6
1.3
300
300
50
*Input filtering on both the SCLOCK and SDATA inputs surpresses noise spikes less than 50 ns.
tBUF
tSUP
SDATA (I/O)
MSB
tDSU
tPSU
LSB
MSB
tDSU
2-7
9
tSUP
STOP
START
CONDITION CONDITION
1
S(R)
REPEATED
START
Figure 79. I2C Compatible Interface Timing
REV. A
tR
tRSU
8
tL
tF
tDHD
tH
1
PS
ACK
tDHD
tSHD
SCLK (I)
tR
–79–
tF
ADuC834
OUTLINE DIMENSIONS
52-Lead Metric Quad Flat Package [MQFP]
(S-52)
Dimensions shown in millimeters
14.15
13.90 SQ
13.65
2.45
MAX
39
27
40
SEATING
PLANE
C02942–0–4/03(A)
1.03
0.88
0.73
26
7.80
REF
10.20
10.00 SQ
9.80
TOP VIEW
(PINS DOWN)
VIEW A
PIN 1
52
14
1
0.23
0.11
13
0.65 BSC
0.38
0.22
2.10
2.00
1.95
7
0
0.10 MIN
COPLANARITY
VIEW A
ROTATED 90 CCW
COMPLIANT TO JEDEC STANDARDS MO-022-AC-1
56-Lead Lead Frame Chip Scale Package [LFCSP]
8 8 mm Body
(CP-56)
Dimensions shown in millimeters
8.00
BSC SQ
0.60 MAX
0.60 MAX
43
7.75
BSC SQ
TOP
VIEW
0.20
REF
12 MAX
6.25
6.10 SQ
5.95
BOTTOM
VIEW
0.50
0.40
0.30
1.00
0.90
0.80
PIN 1
INDICATOR
56 1
42
PIN 1
INDICATOR
0.30
0.23
0.18
29
28
15 14
6.50
REF
0.70 MAX
0.65 NOM
0.05 MAX
0.02 NOM
0.50 BSC
SEATING
PLANE
COPLANARITY
0.08
COMPLIANT TO JEDEC STANDARDS MO-220-VLLD-2
Revision History
Location
Page
4/03—Data Sheet changed from REV. 0 to REV. A.
Updated OUTLINE DIMENSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
–80–
REV. A