MAXIM MAX1402EVKIT

19-1440; Rev 0; 3/99
MAX1402 EV System
The MAX1402 evaluation system (EV system) is a complete, multichannel data-acquisition system consisting of
a MAX1402 evaluation kit (EV kit) and a Maxim 68HC16
microcontroller (µC) module. The MAX1402 is a lowpower, multichannel, serial-output analog to digital converter (ADC). Windows 95/98™-compatible software provides a handy user interface to exercise the MAX1402’s
features. Source code in C++ and 68HC11 assembly language is provided for the low-level portion of the software.
Order the EV system for comprehensive evaluation of
the MAX1402 using a personal computer. Order only
the EV kit if the 68HC16 µC Module has already been
purchased with a previous Maxim EV system, or for
custom use in other µC-based systems.
The MAX1402 EV kit and EV system can also be used
to evaluate the MAX1400. Simply order a free sample of
the MAX1400CAI along with the MAX1402 EV kit.
Features
♦ Easy to Configure
♦ Collects Up to 8192 Samples at Full Speed
♦ Complete Evaluation System
♦ Proven PC Board Layout
♦ Fully Assembled and Tested
Ordering Information
PART
TEMP. RANGE
MAX1402EVKIT
0°C to +70°C
User-Supplied
MAX1402EVC16
0°C to +70°C
Windows Software
Note: The MAX1402 software can only be used with the complete evaluation system (MAX1402EVC16), which includes the
68HC16MODULE-DIP together with the MAX1402EVKIT.
MAX1402 EV Kit
Parts List
MAX1402 Stand-Alone EV Kit
The MAX1402 EV kit provides a proven PC board layout
to facilitate evaluation of the MAX1402 with user-provided software and hardware. It must be interfaced to
appropriate timing signals for proper operation. Refer to
the MAX1402 data sheet for timing requirements. See
Table 2, Jumper Functions.
MAX1402 EV System
The MAX1402 EV system operates from a user-supplied +8V to +12V DC power supply.
MAX1402 EV System
Component List
PART
QTY
DESCRIPTION
MAX1402EVKIT
1
MAX1402 Evaluation Kit
68HC16MODULE-DIP
1
68HC16 µC Module
Windows 95/98 is a trademark of Microsoft Corp.
INTERFACE TYPE
DESIGNATION QTY
DESCRIPTION
C3–C8
6
100pF ceramic capacitors (1206)
C9, C10, C11
3
0.1µF ceramic capacitors (1206)
C12, C13
0
Not installed
C15
1
2.2µF aluminum electrolytic radial
leaded capacitor
J1
1
2x20 right-angle socket
J2
1
Female SMA connector
JU1–JU8
0
Not installed
R1–R6
6
100Ω 5% resistors (1206)
R7, R8
2
10Ω 5% resistors (1206)
R9
0
Not installed
R10
0
Not installed
Component
Suppliers
U1
1
Maxim MAX1402CAI
U2
1
Maxim MAX6025AEUR
(SOT-23 voltage reference, 2.500V,
20ppm/°C max)
Y1
1
2.4576MHz ceramic resonator
Murata # CST2.45MGW040
None
1
3" x 4" PC board
MAX1402 Evaluation Kit
None
1
3 1/2" software disk
MAX1402 Evaluation Kit
None
1
Maxim 68HC16 module monitor ROM,
Version 2.0 (Version 1.0 ROM will not
work with this EV kit.)
________________________________________________________________ Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
Evaluates: MAX1400/MAX1402
General Description
MAX1402 EV System
Evaluates: MAX1400/MAX1402
MAX1402 EV Kit Files
Windows Application Program Files
FILE
DESCRIPTION
MAX1402.EXE
Application program that runs under
Windows 95/98.
MAX1402.HLP
Help file
KIT1402.C16
Software loaded into 68HC16 microcontroller.
MAX1402.INI
Program settings file
Example Source Code Files
FILE
DESCRIPTION
MAX1402.CPP
Source code module for driving the
MAX1402, provided for reference. Includes
definitions of the register names and lowlevel access routines. Compiled with
Borland C++ 4.52. Maxim holds the copyright but allows customers to adapt the program for their own use without charge.
MAX1402.H
Header file for MAX1402.CPP, provided for
reference.
68HC16 Source Code Files
FILE
DESCRIPTION
KIT1402.ASM
Main source code for the KIT1402.C16 program, provided for reference. Maxim holds
the copyright but allows customers to
adapt the program for their own use without
charge.
EVKIT.ASM
Source code defining the program interface with the Maxim 68HC16 Module ROM
(Rev. 2.0).
Install/Uninstall Program Files
FILE
2
DESCRIPTION
INSTALL.EXE
Installs the EV kit files on your computer.
UNINST.INI
Database for uninstall program.
UNMAXIM.EXE
Removes the EV kit files from your computer. This file is automatically copied to
C:\WINDOWS during installation.
_________________________Quick Start
Recommended Equipment
Obtain the following equipment before you begin:
• A DC power supply that generates +8VDC to
+12VDC at 30–50mA
• An IBM PC-compatible computer running Windows
95/98
• A spare serial communications port, preferably a
9-pin plug
• A serial cable to connect the computer’s serial port
to the Maxim 68HC16 Module
1) Before you begin, make sure your 68HC16 module
has the Rev. 2.0 ROM. The software will not function
with the Rev. 1.0 ROM.
2) Carefully connect the boards by aligning the 40-pin
header of the MAX1402 EV kit with the 40-pin connector of the 68HC16MODULE module. Gently
press them together. The two boards should be
flush against one another.
3) Connect the DC power source to the µC module at
terminal block J2, located next to the ON/OFF
switch, along the top edge of the µC module.
Observe the polarity marked on the board.
4) Connect a cable from the computer’s serial port to
the µC module. If using a 9-pin serial port, use a
straight-through, 9-pin female-to-male cable. If the
only available serial port uses a 25-pin connector, a
standard 25-pin to 9-pin adapter will be required.
The EV kit software checks the modem status lines
(CTS, DSR, DCD) to confirm that the correct port
has been selected.
5) Install the software on your computer by running the
INSTALL.EXE program from the floppy disk. The
program files are copied and icons are created for
them in the Windows 95/98 Start Menu. The EV kit
software evaluates both the MAX1402 and the
MAX1400.
6) Start the MAX1402 program by opening its icon in
the Start Menu.
7) The program will prompt you to connect the µC
module and turn its power on. Slide SW1 to the “ON”
position. Select the correct serial port, and click OK.
The program will automatically download the file
KIT1402.C16 to the module.
_______________________________________________________________________________________
MAX1402 EV System
Upgrading the 68HC16 Module
The MAX1402 Evaluation kit requires Rev. 2.0 of the
Maxim 68HC16 Module ROM. Check the label on
device U3 on the module; if its label says “Rev. 1.0,” it
must be replaced.
The Rev. 2.0 ROM is a 28-pin DIP that comes with the
evaluation kit. If it was omitted, contact the factory for a
replacement.
To install the new ROM, use the following procedure.
Use antistatic handling precautions. To reduce the risk
of ESD damage, gather all required materials and perform the installation at one sitting.
1) Slide the ON/OFF switch to the OFF position.
2) Using a flat-blade screwdriver, gently pry U3, the
REV 1.0 ROM, out of its socket.
3) Remove the REV 2.0 ROM from its antistatic packaging.
4) Align the REV 2.0 ROM in the U3 socket pins.
Observe correct polarity (the notch at the top of the
ROM). Verify that the pins are lined up with the
socket, and gently press the ROM into place.
Proceed to the regular Quick Start instructions.
Detailed Description
_________________________of Software
The MAX1402 digitizes up to seven inputs. The various
program functions are grouped into windows, which are
accessible from the Show menu on the main menu bar.
Main Display
The main display shows the calculated input voltage
and raw A/D output code for each active channel.
Although there are nine input channels, only certain
configurations are allowed.
Select any single channel or one of the scanning
sequences from the Inputs menu. AIN 1-6 designates
an analog input between the AIN1 pin and the AIN6 pin.
CALOFF designates the signal between the CALOFF+
and CALOFF- pins. CALGAIN designates the signal
between the CALGAIN+ and CALGAIN- pins.
The EV kit software assumes that CALOFF+ and
CALOFF- are grounded so that CALOFF measures zero
volts. Similarly, the software assumes that CALGAIN+ is
connected to REFIN+ and CALGAIN- is connected to
REFIN- so that CALGAIN measures the reference voltage. These two points calibrate the code-to-voltage
translation function performed in the software.
The MAX1400/MAX1402 automatically triggers its measurements, unless the FSYNC control bit is set. The
evaluation kit software communicates with the
MAX1400/MAX1402 at intervals determined by the
Update Every combo box. To halt this automatic update,
uncheck the Update Every checkbox or change the
Update Every to a value between 100ms and 60000ms.
Normally, the microcontroller collects new data as soon
as it becomes available, by using the INT pin to trigger
an interrupt service routine. If the INT pin is not used as
an interrupt, then the MAX1400 must not be operated in
free-running mode. Check or uncheck the Use INT
Interrupt checkbox to configure the evaluation kit software.
Configuration Tool
The Configuration Tool controls parameters that apply
to the entire EV kit. Like the other windows, the
Configuration Tool can be activated from the Show
menu of the main menu bar. The CLK control should
match the external ceramic resonator or crystal that
sets the master clock frequency. The VREF Reference
Voltage control tells the software what the reference
voltage is. This is used to convert the raw A/D output
codes into the corresponding input voltage to speed
user evaluation. The Data Rate control determines how
often the MAX1402 performs a measurement. Some
data rates provide 16-bit, noise-free resolution when
used with the SINC3 filter (discussed below). The Filter
Sync control can be used to inhibit the MAX1402 from
performing its self-timed measurements. The Buffer
Inputs checkbox enables the internal input buffers. The
Burnout Test Currents checkbox enables two small
(0.1µA) current sources to provide an input stimulus.
When used with a transducer, these current sources
can be used to verify that the transducer has not failed
open or short circuit.
At the bottom of the window, there are input voltage
range selection buttons. These buttons configure all
input channels for the same input voltage range.
Although the MAX1400/MAX1402 can be operated with
three different input ranges at the same time, the evaluation kit software only supports a single range for all
channels.
The digital filter on the MAX1402 can be configured for
SINC3 or SINC1 operation, which affects the filter cutoff
_______________________________________________________________________________________
3
Evaluates: MAX1400/MAX1402
8) When the software successfully establishes communication with the EV kit board, you will see a configuration tool and some other windows. Verify that the
CLKIN and Reference Voltage settings are correct.
Close or minimize this dialog box.
9) Apply input signals to the inputs labeled AIN1–AIN5,
at the bottom edge of the MAX1402 EV kit board.
AIN6 is analog common. Observe the readout on
the screen.
Evaluates: MAX1400/MAX1402
MAX1402 EV System
frequency. (SINC' means SIN(X) ÷ X, and SINC3 means
(SIN(X) ÷ X)3.) The SINC3 filter is required for 16-bit accuracy. The SINC1 filter provides faster settling time with less
accuracy. Alternatively, the raw modulator output can be
driven out the DOUT pin; however, the EV kit software
cannot read data from the MAX1402 in this mode.
Calibration Tool
The MAX1402 EV kit software can average the measurements from the calibration channels and use the
measured values to correct the voltage displays. The
calibration algorithm assumes that the CALOFF inputs
are externally connected together, and that the
CALGAIN inputs are externally connected to the reference voltage (VREF). View the calibration tool by
selecting it from the Show menu.
The software automatically disables calibration if either
of the calibration channels reports a code of 0 or
262143. This is to prevent erroneous calibration when
using a transfer function that does not include both 0V
and VREF.
When Use CALOFF and CALGAIN for Calibration is
checked, the software averages the raw A/D codes for
the CALOFF and CALGAIN channels. The average is
calculated as a weighted sum of the new data and the
old average value. The Slower/Faster slide bar controls
the weight of the new data vs. the weight of the old
average.
The EV kit software assumes that all three transfer function registers are set to the same value.
This calibration affects only the displayed voltage, not
the raw code numbers. The average CALOFF and
CALGAIN code values are used as the endpoints of a
linear interpolation, with CALOFF measuring zero volts
and CALGAIN measuring VREF.
The linear interpolation formula is as follows:
Voltage =
VREF ⋅ (Code − CALOFFcode)
(CALGAINcode − CALOFFcode) ⋅ PGAgain
Sampling Tool
To sample data at full speed, select Sample from the
main display menu, make your selections, and click on
the Begin Sampling button. Sampling rate is controlled
by the Configuration tool. Sample size is restricted to a
power of two. Sample Size controls the number of samples collected on each selected channel. After the
samples have been collected, the data is automatically
uploaded to the host and is graphed. Once displayed,
the data may be saved to a file.
4
While the Sampling tool is open, the other windows are
locked out. Close the Sampling tool by clicking the
Close icon in the upper corner.
Register Display Tool
This tool displays all of the internal registers of the
MAX1400/MAX1402. Modify any bit value by checking
or unchecking its box. (The START bit and the zero bits
in the special function register (SFR) cannot be modified). The Read All Registers button causes the software to read all of the MAX1400/MAX1402’s registers.
(Not functional when the MDOUT or FULLPD bit is set.)
Refer to Table 4, Guide to Register Bit Functions.
Communications Register (COMMS)
Setting the FSYNC control bit inhibits the MAX1400/
MAX1402 from performing its self-timed measurements.
If FSYNC = 1 when it is time to perform a measurement,
the MAX1400/MAX1402 simply skips that measurement. Thus, power line frequency rejection is not affected by the FSYNC bit.
Setting the STDBY bit places the part in low-power
standby mode. The serial interface and the CLK oscillator continue to operate. The part can be restored to
normal operation by clearing the STDBY bit.
Special Function Register (SFR)
Setting the MDOUT bit causes the raw modulator output
to be driven out the DOUT pin; however, the EV kit software cannot read data from the MAX1402 in this mode.
Setting the FULLPD bit in the SFR register places the
part in full power-down mode. The master oscillator
does not run. To restore normal operation, click on the
Reset menu item in the main display. This causes the
68HC16 software to pulse the MAX1402 RESET pin.
Transfer Function Registers (TF1, TF2, TF3)
The three Transfer Function registers (TF1, TF2, TF3)
control how input voltage is mapped to code values. The
transfer function registers control a programmable-gain
amplifier (PGA) and an offset correction DAC.
If U/B = 1, the transfer function maps unipolar voltages
between 0V and VREF. If U/B = 0, then the transfer
function maps bipolar voltages between -VREF and
+VREF. Next, the PGA increases the code-per-volt processing gain, reducing the full-scale voltage range by a
factor of 1, 2, 4, 8, 16, 32, 64, or 128. Finally, the offset
correction DAC offsets the voltage range by up to ±7/6
of the full-scale voltage range.
_______________________________________________________________________________________
MAX1402 EV System
Detailed Description
________________________of Hardware
U1, the MAX1402, is a multichannel, high-resolution
A/D converter (refer to the MAX1402 data sheet). U2,
the MAX6025, is a 2.5V reference (refer to the
MAX6025 data sheet). Y1 contains a ceramic resonator
and its load capacitors. R1–R6 together with C3–C8
form anti-aliasing input filters. R8 and C11 filter the digital power supply. The analog supply comes through filter R7/C10.
Input Filtering
The EV kit has an RC filter on each input with a time
constant of approximately 0.01µs = 10ns (R = 100Ω,
C = 100pF). When scanning between channels, the RC
filter’s settling time may increase the acquisition time
required for full accuracy.
Evaluating the MAX1400
The MAX1400 can be evaluated by shorting across
jumpers JU6 and JU7. The MAX1400 is exactly like the
MAX1402, except that the function of pins 5, 6, 7, and 8
is changed. Instead of the OUT1/OUT2 outputs and
DS0/DS1 inputs, these pins are used to provide access
to the analog signal between the multiplexer and the
A/D converter. Tables 2 and 3 list the jumper functions
and default settings. Refer to the MAX1400 data sheet
for detailed information.
Measuring Supply Current
Supply current can be estimated by measuring the voltage across a series resistor. On the EV kit board, the
MAX1402 draws all of its analog and digital power
through R8, which is 10Ω. In addition, all analog supply
current flows through R7, which is also 10Ω.
Troubleshooting
Problem: unacceptable amounts of noise in the signal.
Collect a sample of 1024 measurements at a 60Hz data
rate. Observe whether the problem is caused by 60Hz
noise.
Any AC-powered equipment connected to the analog
signal ground can inject noise. Try replacing AC-powered DVMs with battery-powered DVMs.
_______________________________________________________________________________________
5
Evaluates: MAX1400/MAX1402
Input pins AIN1 and AIN2 are controlled by TF1. Input
pins AIN3 and AIN4 are controlled by TF2. Input pin
AIN5 is controlled by TF3. Input pin AIN6 is the analog
common.
When SCAN = 1, the CALOFF and CALGAIN channels
are controlled by TF3. When SCAN = 0, the CALOFF
and CALGAIN channels are controlled by one of the
transfer function registers, as selected by the A1 and
A0 bits.
For simplicity, the EV kit software assumes that all three
transfer functions are configured alike.
Evaluates: MAX1400/MAX1402
MAX1402 EV System
Table 2. Jumper Functions
JUMPER
STATE
JU1
Closed*
JU1
Open
JU2
Closed*
JU2
Open
JU3
Closed*
JU3
Open
JU4
Closed*
FUNCTION
Use CalGain inputs for gain calibration (CALGAIN+ = REFIN+)
Use CalGain inputs as general purpose signal inputs
Use CalGain inputs for gain calibration (CALGAIN- = REFIN-)
Use CalGain inputs as general purpose signal inputs
Use CalOff inputs for offset calibration (CALOFF+ = GND)
Use CalOff inputs as general purpose signal inputs
Use CalOff inputs for offset calibration (CALOFF- = GND)
JU4
Open
JU5
Closed*
JU5
Open
JU6
Closed
Connects pin 5 to pin 7
MAX1402: pin 5 = digital input DS1, pin 7 = current source
MAX1400: normal operation
JU6
Open
Disconnects pin 5 from pin 7
MAX1402: pin 5 = digital input DS1, pin 7 = current source
MAX1400: insert filter between mux and A/D
JU7
Closed
Connects pin 6 to pin 8
MAX1402: pin 6 = digital input DS0, pin 8 = current source
MAX1400: normal operation
JU7
Open
Disconnects pin 6 from pin 8
MAX1402: pin 6 = digital input DS0, pin 8 = current source
MAX1400: insert filter between mux and A/D
JU8
Closed*
JU8
Open
Use CalOff inputs as general purpose signal inputs
Use on-board reference U2 (REFIN- = GND)
REFIN+ and REFIN- must be driven by an external reference
Use on-board reference U2 (REFIN+ = 2.5V)
REFIN+ and REFIN- must be driven by an external reference
* Default trace on top layer of PC board
Table 3. Default Jumper Settings
JUMPER
STATE
FUNCTION
JU1
Closed*
Use CalGain inputs for gain calibration (CALGAIN+ = REFIN+)
JU2
Closed*
Use CalGain inputs for gain calibration (CALGAIN- = REFIN-)
JU3
Closed*
Use CalOff inputs for offset calibration (CALOFF+ = GND)
JU4
Closed*
Use CalOff inputs for offset calibration (CALOFF- = GND)
JU5
Closed*
Use on-board reference U2 (REFIN- = GND)
JU6
Open
Disconnects pin 5 from pin 7
MAX1402: pin 5 = digital input DS1, pin 7 = current source
MAX1400: insert filter between mux and A/D
JU7
Open
Disconnects pin 6 from pin 8
MAX1402: pin 6 = digital input DS0, pin 8 = current source
MAX1400: insert filter between mux and A/D
JU8
Closed*
Use on-board reference U2 (REFIN+ = 2.5V)
* Default trace on top layer of PC board
6
_______________________________________________________________________________________
MAX1402 EV System
REGISTER
BIT NAME
COMMS
0/DRDY
RS2–RS0
R/W
GS1
GS2
SFR
Evaluates: MAX1400/MAX1402
Table 4. Guide to Register Bit Functions
DESCRIPTION
Start bit is zero; DIN pin must be 1 when idle
Register select for subsequent operation
Selects subsequent read or write operation
RESET
Causes software reset when set to 1
STDBY
Activates standby power-down mode when set to 1
FSYNC
Inhibits the A/D converter when set to 1
A1
Selects the active channel
A0
Selects the active channel
MF1
Selects the data output rate
MF0
Selects the data output rate
CLK
Selects the CLKIN frequency
FS1
Select the data output rate
FS0
Select the data output rate
FAST
Selects SINC1 filter instead of SINC3
SCAN
Enables the scanning sequences
M1
Enables the CalGain channel
M0
Enables the CalOff channel
BUFF
Enables the input buffers
DIFF
Selects differential input pairs
BOUT
Enables the transducer burn-out test currents
IOUT
Enables the OUT1 and OUT2 current sources (MAX1402 only)
X2CLK
Selects the CLKIN frequency
MDOUT
Changes the DOUT and INT pins to provide raw modulator output
FULLPD
Activates full power-down mode. Use hardware reset to restore normal operation.
All other bits in SFR must be zero
TF1, 2, 3
G2–G0
U/B
DATA
Select the PGA Gain
Selects unipolar or bipolar coding
D3–D0
Select the offset correction DAC code; D3 = sign, D2–D0 = magnitude
D17–D0
Raw code value
DS1
Value of the DS1 input pin (MAX1402 only)
DS0
Value of the DS0 input pin (MAX1402 only)
CID2–CID0
Channel identification tag
_______________________________________________________________________________________
7
8
AIN4
AIN3
AIN2
AIN1
OUT1
OUT2
DS0
DS1
J1-33
J1-34
AVDD
R1
100Ω
R4
100Ω
R3
100Ω
R2
AGND
JU7
AGND
AGND
AGND
AGND
JU6
DGND
100Ω
2
Y1
2.4576MHz
1
3
C6
100pF
C5
100pF
C4
100pF
14
13
12
11
10
9
8
7
6
5
4
3
2
1
AIN4
AIN3
AIN2
AIN1
V+
AGND
OUT1/ADCIN-
OUT2/ADCIN+
DS0/MUXOUT-
DGND
VDD
INT
DOUT
DIN
SCLK
AIN5
AIN6
CALGAIN-
CALGAIN+
REFIN-
REFIN+
CALOFF-
CALOFF+
MAX1402
U1
DS1/MUXOUT+
RESET
CS
CLKOUT
CLKIN
DGND
EXTCLK
C3
100pF
J2
15
16
17
18
19
20
21
22
23
24
25
26
27
28
C7
100pF
C8
100pF
C12
OPEN
R10
DVDD
10Ω
R7
R9
AGND
AGND
R6
100Ω
R5
100Ω
SHORT
C9
0.1µF
JU4
C13 SHORT
OPEN
DGND
INT
MISO
MOSI
SCLK
JU2
JU1
AGND
JU3
C10
0.1µF
J1-29
J1-35
J1-36
J1-37
AIN5
AIN6
AVDD
DVDD
C11
0.1µF
GAIN-
GAIN+
REF-
REF+
OFFSET-
OFFSET+
DGND
10Ω
R8
JU5
JU8
1
VIN
GND
3
2
VOUT
MAX6025
U2
J1-8
J1-7
AGND
C15
2.2µF
J1-6
J1-5
J1-4
J1-3
J1-2
J1-1
Evaluates: MAX1400/MAX1402
MAX1402 EV System
Figure 1. MAX1402 EV Kit Schematic
_______________________________________________________________________________________
MAX1402 EV System
Evaluates: MAX1400/MAX1402
1.0"
Figure 2. MAX1402 EV Kit Component Placement Guide—Component Side
_______________________________________________________________________________________
9
Evaluates: MAX1400/MAX1402
MAX1402 EV System
1.0"
Figure 3. MAX1402 EV Kit PC Board Layout—Component Side
10
______________________________________________________________________________________
MAX1402 EV System
Evaluates: MAX1400/MAX1402
1.0"
Figure 4. MAX1402 EV Kit PC Board Layout—Solder Side
______________________________________________________________________________________
11
Evaluates: MAX1400/MAX1402
MAX1402 EV System
NOTES
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
12 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 1999 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.