HOLTEK HT49C50

HT49C50
8-Bit Microcontroller
Features
·
·
·
·
·
·
·
·
·
·
·
Operating voltage: 2.2V~5.2V
8 input lines
12 bidirectional I/O lines
Two external interrupt input
Two 8-bit programmable timer/event
counter with PFD (programmable frequency divider) function
LCD driver with 33 ´ 3 or 32 ´ 4 segments
4K ´ 15 program memory ROM
160 ´ 8 data memory RAM
Real Time Clock (RTC)
8-bit prescaler for RTC
Watchdog timer
·
·
·
·
·
·
·
·
·
·
Buzzer output
On-chip crystal and RC oscillator
Halt function and wake-up feature reduce
power consumption
6-level subroutine nesting
Bit manipulation instruction
15-bit table read instruction
Up to 1ms instruction cycle with 4MHz
system clock
63 powerful instructions
All instructions in 1 or 2 machine cycles
80/100-pin QFP package
General Description
tions among which are calculators, clock timers,
games, scales, leisure products, other hand held
LCD products, and battery system in particular.
The HT49C50 is an 8-bit high performance single
chip microcontroller. Its single cycle instruction
and two-stage pipeline architecture make it suitable for high speed applications. The device is
suited for use in multiple LCD low power applica-
1
August 18, 1999
HT49C50
Block Diagram
T im e r C L K 0 ~ 1
In te rru p t
C ir c u it
P ro g ra m
C o u n te r
P ro g ra m
R O M
M
T M R 0
T M R 1
S T A C K
IN T C
U
X
T M R 0 ~ 1
T M R 0 C
T M R 1 C
S Y S C L K /4
R T C
In s tr u c tio n
R e g is te r
M
M P
U
X
D A T A
M e m o ry
M
W D T
T im e B a s e
P O R T B
T im in g
G e n e r a tio n
S h ifte r
O S C 3
O S C 4
P C 0 ~ P C 3
S T A T U S
A L U
R T C O S C
X
W D T O S C
P C
M U X
In s tr u c tio n
D e c o d e r
U
P B 0 /IN T 0
P B 1 /IN T 1
P B 2 /T M R 0
P B 3 /T M R 1
P B
P B 4 ~ P B 7
B P
O S C 2
O S
R E
V D
V S
D
S
C 1
P O R T A
A C C
P A
L C D
M e m o ry
S
L C D
C O M 0 ~
C O M 2
P A 0
P A 1
P A 2
P A 3
P A 4
/B Z
/B Z
/P F D
~ P A 7
D R IV E R
C O M 3 ~
S E G 3 2
S E G 0 ~
S E G 3 1
2
August 18, 1999
HT49C50
Pin Assignment
O
O
O
O
S
E G
N
N
N
N
S C
S C
V D
S C
S C
R E
N
C
C
C
C
N C
N C
N C
N C
D
C
S
4
3
2
1
0
P
P
P
P B
P B
P A 0 /B
P A 1 /B
P A
A 3 /P F
P A
P A
P A
P A
B 0 /IN T
B 1 /IN T
2 /T M R
3 /T M R
P B
P B
P B
P B
P C
P C
P C
P C
V S
N
N
N
8 0
Z
1
Z
3
6 2
4
6 1
5
6 0
6
5 9
7
5 8
8
5 7
9
5 6
1 0
5 5
4
5
6
7
0
1
0
4
1
6
7
0
1
2
C
C
C
S
1 1
1 2
1 3
5
3
6 4
6 3
2
D
7 9 7 8 7 7 7 6 7 5 7 4 7 3 7 2 7 1 7 0 6 9 6 8 6 7 6 6 6 5
2
H T 4 9 C 5 0
8 0 Q F P
5 4
5 3
5 2
1 4
5 1
1 5
5 0
1 6
4 9
1 7
4 8
1 8
4 7
1 9
4 6
2 0
4 5
2 1
4 4
2 2
4 3
2 3
4 2
4 1
2 4
2 5 2 6 2 7 2 8 2 9 3 0 3 1 3 2 3 3 3 4 3 5 3 6 3 7 3 8 3 9 4 0
S E G
S E G
S E G
S E G
S E G
S E G
S E G
S E G
S E G
S E G
S E G
S E G
S E G
S E G
S E G
S E G
S E G
S E G
S E G
S E G
S E G
S E G
S E G
S E G
1
2
3
4
5
6
7
8
9
1 0
1 1
1 2
1 3
1 4
1 5
1 6
1 7
1 8
1 9
2 0
2 1
2 2
2 3
2 4
S E G
S E G
S E G
S E G
S E G
S E G
S E G
S E G
C O M
C O M
C O M
C 2
C 1
V 2
V 1
V L C
D
2 5
2 6
2 7
2 8
2 9
3 0
3 1
3 2 /C O M 3
2
1
0
3
August 18, 1999
HT49C50
O
O
O
O
N
N
N
N
N
N
N
S C
S C
V D
S C
S C
R E
N
D
C
N C
N C
N C
N C
N C
N C
C
C
C
C
C
C
C
S
3
N C
P
P A 3 /P
P
P
P
P
P B 0 /IN
P B 1 /IN
P B 2 /T M
P B 3 /T M
P
P
P
P
P
P
P
P
4
2
N C
P A 0
P A 1
3
1
N C
N C
/B Z
/B Z
A 2
F D
A 4
A 5
A 6
A 7
T 0
T 1
R 0
R 1
B 4
B 5
B 6
B 7
C 0
C 1
C 2
C 3
N C
N C
N C
N C
N C
2
1
1 0 0 9 9 9 8 9 7 9 6 9 5 9 4 9 3 9 2 9 1 9 0 8 9 8 8 8 7 8 6 8 5 8 4 8 3 8 2 8 1
N C
4
8 0
N C
7 9
N C
7 8
N C
S E
S E
S E
S E
S E
S E
S E
S E
S E
S E
S E
S E
S E
S E
S E
S E
S E
S E
S E
S E
S E
S E
S E
S E
7 7
5
7 6
6
7 5
7
7 4
8
7 3
9
7 2
1 0
7 1
1 1
7 0
1 2
1 3
1 4
1 5
6 9
H T 4 9 C 5 0
1 0 0 Q F P
6 8
6 7
6 6
1 6
6 5
1 7
6 4
1 8
6 3
1 9
6 2
2 0
6 1
2 1
6 0
2 2
5 9
2 3
5 8
2 4
5 7
2 5
5 6
2 6
5 5
2 7
5 4
2 8
5 3
2 9
3 0
5 2
3 1 3 2 3 3 3 4 3 5 3 6 3 7 3 8 3 9 4 0 4 1 4 2 4 3 4 4 4 5 4 6 4 7 4 8 4 9 5 0
5 1
G 0
G 1
G 2
G 3
G 4
G 5
G 6
G 7
G 8
G 9
G 1 0
G 1 1
G 1 2
G 1 3
G 1 4
G 1 5
G 1 6
G 1 7
G 1 8
G 1 9
G 2 0
G 2 1
G 2 2
G 2 3
N C
N C
N C
N C
S E G 2
S E G 2
S E G 2
S E G 2
S E G 2
S E G 2
S E G 3
S E G 3
S E G 3
C O M 2
C O M 1
C O M 0
C 2
C 1
V 2
V 1
V L C D
V S S
N C
4
5
6
7
8
9
0
1
2 /C O M 3
4
August 18, 1999
HT49C50
Pad Assignment
4
P A 4
5
P A 5
6
6 5
6 4
6 3
S E G 0
P A 3 /P F D
6 6
O S C 4
3
6 7
O S C 3
P A 2
6 8
V D D
2
O S C 2
P A 1 /B Z
O S C 1
1
R E S
P A 0 /B Z
6 2
6 1
S E G 1
6 0
S E G 2
5 9
S E G 3
5 8
S E G 4
5 7
S E G 5
5 6
S E G 6
P A 6
7
5 5
S E G 7
P A 7
8
5 4
S E G 8
P B 0 /IN T 0
9
5 3
S E G 9
P B 1 /IN T 1
1 0
5 2
S E G 1 0
P B 2 /T M R 0
1 1
5 1
S E G 1 1
P B 3 /T M R 1
1 2
5 0
S E G 1 2
P B 4
1 3
4 9
S E G 1 3
P B 5
1 4
4 8
S E G 1 4
P B 6
1 5
4 7
S E G 1 5
P B 7
1 6
4 6
S E G 1 6
4 5
S E G 1 7
P C 0
1 7
P C 1
1 8
P C 2
P C 3
(0 ,0 )
1 9
2 0
2 6
2 7
2 8
2 9
3 0
3 1
3 2
3 3
3 4
3 5
3 6
3 7
3 8
C 2
C O M 0
C O M 1
C O M 2
S E G 3 2 /C O M 3
S E G 3 1
S E G 3 0
S E G 2 9
S E G 2 8
S E G 2 7
S E G 2 6
S E G 2 5
S E G 2 4
V 2
2 5
C 1
2 4
V 1
V S S
2 3
V L C D
2 1
2 2
4 4
S E G 1 8
4 3
S E G 1 9
4 2
S E G 2 0
4 1
S E G 2 1
4 0
S E G 2 2
3 9
S E G 2 3
* The IC substrate should be connected to VSS in the PCB layout artwork.
5
August 18, 1999
HT49C50
Pin Description
Mask
Option
Description
Wake-up
Pull-high
or None
CMOS or
NMOS
PA0~PA7 constitute an 8-bit bidirectional input/output port
with Schmitt trigger input capability. Each bit on port can be
configured as a wake-up input by mask option. PA0~PA3 can be
configured as a CMOS output or NMOS input/output with or
without pull-high resistor by mask option. PA4~PA7 are always pull-high NMOS input/output. Of the eight bits,
PA0~PA1 can be set as I/O pins or buzzer outputs by mask option. PA3 can be set as an I/O pin or as a PFD output also by
mask option.
I
¾
PB0~PB7 constitute an 8-bit Schmitt trigger input port. Each
bit on port are pull-high resistor. Of the eight bits, PB0 and PB1
can be set as input pins or as external interrupt control pins
(INT0) and (INT1) respectively, by software application. PB2
and PB3 can be set as an input pin or as a timer/event counter
input pin TMR0 and TMR1 also by software application.
I/O
Pull-high
or None
CMOS or
NMOS
PC0~PC3 constitute a 4-bit bidirectional input/output port
with a schmitt trigger input capability. On the port, such can be
configured as CMOS output or NMOS input/output with or
without pull-high resistor by mask option.
VSS
I
¾
Negative power supply, GND
VLCD
I
¾
LCD power supply
V1,V2,C1,C2
I
¾
Voltage pump
SEG32/COM3
COM2~COM0
O
1/3 or 1/4
Duty
SEG31~SEG0
O
¾
LCD driver outputs for LCD panel segments
OSC4
OSC3
O
I
¾
Real time clock oscillators
VDD
¾
¾
Positive power supply
OSC2
OSC1
O
I
RES
I
Pin Name
PA0/BZ
PA1/BZ
PA2
PA3/PFD
PA4~PA7
PB0/INT0
PB1/INT1
PB2/TMR0
PB3/TMR1
PB4~PB7
PC0~PC3
I/O
I/O
SEG32 can be set as a segment or as a common output driver for
LCD panel by mask option. COM2~COM0 are outputs for LCD
panel plate.
OSC1 and OSC2 are connected to an RC network or a crystal
Crystal or
(by mask option) for the internal system clock. In the case of RC
RC
operation, OSC2 is the output terminal for 1/4 system clock.
¾
Schmitt trigger reset input, active low
6
August 18, 1999
HT49C50
Absolute Maximum Ratings
Supply Voltage........................VSS-0.3V to 5.5V
Storage Temperature.................-50°C to 125°C
Input Voltage .................VSS-0.3V to VDD+0.3V
Operating Temperature ..............-25°C to 70°C
Note: These are stress ratings only. Stresses exceeding the range specified under ²Absolute Maximum Ratings² may cause substantial damage to the device. Functional operation of this device
at other conditions beyond those listed in the specification is not implied and prolonged exposure to extreme conditions may affect device reliability.
D.C. Characteristics
Symbol
Parameter
Ta=25°C
Test Conditions
Typ.
2.2
¾
5.2
V
No load,
fSYS=4MHz
¾
1
2
mA
¾
2.5
5
mA
No load,
fSYS=2MHz
¾
0.75
1.5
mA
¾
1.5
3
mA
No load,
system halt
¾
¾
5
mA
¾
¾
10
mA
No load,
system halt
¾
¾
1
mA
¾
¾
2
mA
Conditions
¾
VDD
Operating Voltage
¾
IDD1
Operating Current
(Crystal OSC)
3V
IDD2
Operating Current (RC OSC)
ISTB1
Standby Current
(RTC Enable, LCD ON)
3V
ISTB2
Standby Current
(RTC Disable, LCD OFF)
3V
VIL
I/O Port Input Low Voltage
VIH
I/O Port Input High Voltage
VIL1
Input Low Voltage
(RES, INT0, INT1, TMR0, TMR1)
VIH1
Input High Voltage
(RES, INT0, INT1, TMR0, TMR1)
IOL
Min.
VDD
5V
3V
5V
5V
5V
Max. Unit
3V
¾
0
¾
0.9
V
5V
¾
0
¾
1.5
V
3V
¾
2.1
¾
3
V
5V
¾
3.5
¾
5
V
3V
RES=0.5VDD
INT0/1=0.3VDD
TMR0/1=0.3VDD
0
¾
1.5/0.9
V
0
¾
2.5/1.5
V
2.4
¾
3
V
4.0
¾
5
V
5V
3V
5V
0.8VDD
3V
VDD=3V,
VOL=0.3V
1.5
2.5
¾
mA
5V
VDD=5V,
VOL=0.5V
4
6
¾
mA
I/O Ports Sink Current
7
August 18, 1999
HT49C50
Symbol
IOH
RPH
Test Conditions
Parameter
VDD
Min.
Typ.
Max. Unit
3V
VDD=3V,
VOH=2.7V
-1
-1.5
¾
mA
5V
VDD=5V,
VOH=4.5V
-2
-3
¾
mA
I/O Ports Source Current
Pull-high Resistance of
I/O Ports and INT0, INT1
Conditions
3V
¾
40
60
80
kW
5V
¾
10
30
50
kW
A.C. Characteristics
Symbol
Parameter
Ta=25°C
Test Conditions
Conditions
VDD
Min.
Typ.
Max.
Unit
3V
VDD=3V
455
¾
4000
kHz
5V
VDD=5V
455
¾
4000
kHz
3V
VDD=3V
400
¾
2000
kHz
5V
VDD=5V
400
¾
3000
kHz
3V
VDD=3V
0
¾
4000
kHz
5V
VDD=5V
0
¾
4000
kHz
3V
VDD=3V
45
90
180
ms
5V
VDD=5V
35
65
130
ms
¾
1
¾
¾
ms
¾
Power-up or
wake-up from halt
¾
1024
¾
tSYS
¾
¾
1
¾
¾
ms
fSYS1
System Clock (Crystal OSC)
fSYS2
System Clock (RC OSC)
fTIMER
Timer I/P Frequency
(TMR0/TMR1)
tWDTOSC
Watchdog Oscillator
tRES
External Reset Low
Pulse Width
¾
tSST
System Start-up
Timer Period
tINT
Interrupt Pulse Width
Note: tSYS= 1/fSYS
8
August 18, 1999
HT49C50
Functional Description
transfer by loading the address corresponding
to each instruction.
Execution flow
The system clock is derived from either a crystal or an RC oscillator. It is internally divided
into four non-overlapping clocks. One instruction cycle consists of four system clock cycles.
The conditional skip is activated by instructions. Once the condition is met, the next instruction, fetched during the current
instruction execution, is discarded and a
dummy cycle replaces it to get a proper instruction; otherwise proceed with the next instruction.
Instruction fetching and execution are
pipelined in such a way that a fetch takes one
instruction cycle while decoding and execution
takes the next instruction cycle. The pipelining
scheme causes each instruction to effectively
execute in a cycle. If an instruction changes the
value of the program counter, two cycles are required to complete the instruction.
The lower byte of the PC (PCL) is a readable
and writeable register (06H). Moving data into
the PCL performs a short jump. The destination is within 256 locations.
When a control transfer takes place, an additional dummy cycle is required.
Program counter - PC
The program counter (PC) is of 12 bits wide and
controls the sequence in which the instructions
stored in the program ROM are executed. The
contents of the PC can specify a maximum of
4096 addresses.
Program memory - ROM
The program memory (ROM) is used to store
the program instructions which are to be executed. It also contains data, table, and interrupt entries, and is organized into 4096 ´ 15
bits which are addressed by the PC and table
pointer.
After accessing a program memory word to
fetch an instruction code, the value of the PC is
incremented by one. The PC then points to the
memory word containing the next instruction
code.
Certain locations in the ROM are reserved for
special usage:
· Location 000H
When executing a jump instruction, conditional
skip execution, loading a PCL register, a subroutine call, an initial reset, an internal interrupt, an external interrupt, or returning from a
subroutine, the PC manipulates the program
S y s te m
O S C 2 (R C
C lo c k
T 1
T 2
T 3
T 4
Location 000H is reserved for program initialization. After chip reset, the program always
begins execution at this location.
T 1
T 2
T 3
T 4
T 1
T 2
T 3
T 4
o n ly )
P C
P C
F e tc h IN S T (P C )
E x e c u te IN S T (P C -1 )
P C + 1
F e tc h IN S T (P C + 1 )
E x e c u te IN S T (P C )
P C + 2
F e tc h IN S T (P C + 2 )
E x e c u te IN S T (P C + 1 )
Execution flow
9
August 18, 1999
HT49C50
· Location 004H
0 0 0 H
Location 004H is reserved for the external interrupt service program. If the INT0 input
pin is activated, and the interrupt is enabled,
and the stack is not full, the program begins
execution at location 004H.
E x te r n a l in te r r u p t 0 s u b r o u tin e
0 0 8 H
E x te r n a l in te r r u p t 1 s u b r o u tin e
0 0 C H
T im e r /e v e n t c o u n te r 0 in te r r u p t s u b r o u tin e
0 1 0 H
· Location 008H
T im e r /e v e n t c o u n te r 1 in te r r u p t s u b r o u tin e
0 1 4 H
Location 008H is reserved for the external interrupt service program also. If the INT1 input pin is activated, and the interrupt is
enabled, and the stack is not full, the program
begins execution at location 008H.
R T C In te rru p t
n 0 0 H
L o o k - u p ta b le ( 2 5 6 w o r d s )
n F F H
Location 00CH is reserved for the timer/event
counter 0 interrupt service program. If a
timer interrupt results from a timer/event
counter 0 overflow, and if the interrupt is enabled and the stack is not full, the program
begins execution at location 00CH.
P ro g ra m
R O M
T im e B a s e In te r r u p t
0 1 8 H
· Location 00CH
L o o k - u p ta b le ( 2 5 6 w o r d s )
F F F H
1 5 b its
N o te : n ra n g e s fro m
0 to F
Program memory
· Location 010H
counter 1 overflow, and if the interrupt is enabled and the stack is not full, the program
begins execution at location 010H.
Location 010H is reserved for the timer/event
counter 1 interrupt service program. If a
timer interrupt results from a timer/event
Mode
D e v ic e in itia liz a tio n p r o g r a m
0 0 4 H
Program Counter
*11 *10
*9
*8
*7
*6
*5
*4
*3
*2
*1
*0
Initial Reset
0
0
0
0
0
0
0
0
0
0
0
0
External Interrupt 0
0
0
0
0
0
0
0
0
0
1
0
0
External Interrupt 1
0
0
0
0
0
0
0
0
1
0
0
0
Timer/event counter 0 overflow
0
0
0
0
0
0
0
0
1
1
0
0
Timer/event counter 1 overflow
0
0
0
0
0
0
0
1
0
0
0
0
Time Base Interrupt
0
0
0
0
0
0
0
1
0
1
0
0
RTC Interrupt
0
0
0
0
0
0
0
1
1
0
0
0
Skip
PC+2
Loading PCL
*11 *10
*9
*8
@7
@6
@5
@4
@3
@2
@1
@0
Jump, Call Branch
#11 #10
#9
#8
#7
#6
#5
#4
#3
#2
#1
#0
Return From Subroutine
S11 S10 S9
S8
S7
S6
S5
S4
S3
S2
S1
S0
Program counter
Notes: *11~*0: Program counter bits
S11~S0: Stack register bits
#11~#0: Instruction code bits
@7~@0: PCL bits
10
August 18, 1999
HT49C50
· Location 014H
Stack register - STACK
Location 014H is reserved for the Time Base
interrupt service program. If a Time Base interrupt occurs, and the interrupt is enabled,
and the stack is not full, the program begins
execution at location 014H.
The stack register is a special part of the memory used to save the contents of the PC. The
stack is organized into 6 levels and is neither
part of the data nor part of the program, and is
neither readable nor writeable. Its activated
level is indexed by a stack pointer (SP) and is
neither readable nor writeable. At a commencement of a subroutine call or an interrupt acknowledgment, the contents of the PC is
pushed onto the stack. At the end of the subroutine or interrupt routine, signaled by a return
instruction (RET or RETI), the contents of the
PC is restored to its previous value from the
stack. After chip reset, the SP will point to the
top of the stack.
· Location 018H
Location 018H is reserved for the real time
clock interrupt service program. If a real time
clock interrupt occurs, and the interrupt is
enabled, and the stack is not full, the program
begins execution at location 018H.
· Table location
Any location in the ROM can be used as a
look-up table. The instructions ²TABRDC
[m]² (the current page, 1 page=256 words)
and ²TABRDL [m]² (the last page) transfer
the contents of the lower-order byte to the
specified data memory, and the contents of
the higher-order byte to TBLH (Table
Higher-order byte register) (08H). Only the
destination of the lower-order byte in the table is well-defined; the other bits of the table
word are all transferred to the lower portion
of TBLH, and the remaining 1 bit is read as
²0². The TBLH is read only, and the table
pointer (TBLP) is a read/write register (07H),
indicating the table location. Before accessing
the table, the location should be placed in
TBLP. All the table related instructions require 2 cycles to complete the operation.
These areas may function as a normal ROM
depending upon the user¢s requirements.
Instruction(s)
If the stack is full and a non-masked interrupt
takes place, the interrupt request flag is recorded but the acknowledgment is still inhibited. Once the SP is decremented (by RET or
RETI), the interrupt is serviced. This feature
prevents stack overflow, allowing the programmer to use the structure easily. Likewise, if the
stack is full, and a ²CALL² is subsequently executed, a stack overflow occurs and the first entry is lost (only the most recent six return
addresses are stored).
Data memory - RAM
The data memory (RAM) is designed with
192´8 bits, and is divided into two functional
groups, namely special function registers and
general purpose data memory, most of which
are readable/writeable, although some are read
only.
Table Location
*11
*10
*9
*8
*7
*6
*5
*4
*3
*2
*1
*0
TABRDC [m]
P11
P10
P9
P8
@7
@6
@5
@4
@3
@2
@1
@0
TABRDL [m]
1
1
1
1
@7
@6
@5
@4
@3
@2
@1
@0
Table location
Notes: *11~*0: Table location bits
P11~P8: Current program Counter bits
@7~@0: Table pointer bits
11
August 18, 1999
HT49C50
0 0 H
0 1 H
0 2 H
0 3 H
0 4 H
0 5 H
0 6 H
0 7 H
0 8 H
0 9 H
0 A H
0 B H
0 C H
0 D H
0 E H
a Table higher-order byte register (TBLH;08H), a
Real time clock control register (RTCC;09H), a
Status register (STATUS;0AH), an Interrupt
control register 0 (INTC0;0BH), a timer/event
counter 0 (TMR0;0DH), a timer/event counter 0
control register (TMR0C;0EH), a timer/event
counter 1 (TMR1;10H), a timer/event counter 1
control register (TMR1C;11H), I/O registers
(PA;12H, PB;14H, PC;16H), and Interrupt control register 1 (INTC1;1EH). On the other hand,
the general purpose data memory, addressed
from 60H to FFH, is used for data and control information under instruction commands.
In d ir e c t A d d r e s s in g R e g is te r 0
M P 0
In d ir e c t A d d r e s s in g R e g is te r 1
M P 1
B P
A C C
P C L
T B L P
T B L H
R T C C
S T A T U S
IN T C 0
S p e c ia l P u r p o s e
D A T A M E M O R Y
T M R 0
T M R 0 C
The areas in the RAM can directly handle
arithmetic, logic, increment, decrement, and
rotate operations. Except some dedicated bits,
each bit in the RAM can be set and reset by
²SET [m].i² and ²CLR [m].i². They are also indirectly accessible through the Memory pointer
register 0 (MP0;01H) or the Memory pointer
register 1 (MP1;03H).
0 F H
1 1 H
T M R 1
T M R 1 C
1 2 H
P A
1 0 H
1 3 H
1 4 H
P B
1 5 H
1 6 H
P C
Indirect addressing register
1 7 H
1 8 H
Location 00H and 02H are indirect addressing
registers that are not physically implemented.
Any read/write operation of [00H] and [02H] accesses the RAM pointed to by MP0 (01H) and
MP1(03H) respectively. Reading location 00H
or 02H indirectly returns the result 00H.
While, writing it indirectly leads to no operation.
: U n u s e d .
1 9 H
1 A H
R e a d a s ² 0 0 ²
1 B H
1 C H
1 D H
1 E H
1 F H
6 0 H
IN T C 1
The function of data movement between two indirect addressing registers is not supported. The
memory pointer registers, MP0 and MP1, are
both 8-bit registers used to access the RAM by
combining corresponding indirect addressing registers. MP0 can only be applied to data memory,
while MP1 can be applied to data memory and
LCD display memory.
G e n e ra l P u rp o s e
D A T A M E M O R Y
(1 6 0 B y te s )
F F H
RAM mapping
Of the two types of functional groups, the special
function registers consist of an Indirect addressing register 0 (00H), a Memory pointer register 0
(MP0;01H), an Indirect addressing register 1
(02H), a Memory pointer register 1 (MP1;03H), a
Bank pointer (BP;04H), an Accumulator
(ACC;05H), a Program counter lower-order byte
register (PCL;06H), a Table pointer (TBLP;07H),
Accumulator - ACC
The accumulator (ACC) is related to the ALU
operations. It is also mapped to location 05H of
the RAM and is capable of operating with immediate data. The data movement between two
data memory locations must pass through the
ACC.
12
August 18, 1999
HT49C50
ations related to the status register, however,
may yield different results from those intended.
The TO and PD flags can only be changed by a
watchdog timer overflow, chip power-up, or
clearing the watchdog timer and executing the
²HALT² instruction. The Z, OV, AC, and C flags
reflect the status of the latest operations.
Arithmetic and logic unit - ALU
This circuit performs 8-bit arithmetic and logic
operations and provides the following functions:
· Arithmetic operations (ADD, ADC, SUB,
SBC, DAA)
· Logic operations (AND, OR, XOR, CPL)
· Rotation (RL, RR, RLC, RRC)
On entering the interrupt sequence or executing the subroutine call, the status register will
not be automatically pushed onto the stack. If
the contents of the status is important, and if
the subroutine is likely to corrupt the status
register, the programmer should take precautions and save it properly.
· Increment and Decrement (INC, DEC)
· Branch decision (SZ, SNZ, SIZ, SDZ etc.)
The ALU not only saves the results of a data operation but also changes the status register.
Status register - STATUS
Interrupts
The status register (0AH) is of 8 bits wide and
contains, a carry flag (C), an auxiliary carry flag
(AC), a zero flag (Z), an overflow flag (OV), a
power down flag (PD), and a watchdog time-out
flag (TO). It also records the status information
and controls the operation sequence.
The HT49C50 provides two external interrupts, two internal timer/event counter interrupts, an internal time base interrupt, and an
internal real time clock interrupt. The interrupt control register 0 (INTC0;0BH) and interrupt control register 1 (INTC1;1EH) both
contain the interrupt control bits that are used
to set the enable/disable status and interrupt
request flags.
Except the TO and PD flags, bits in the status
register can be altered by instructions similar
to other registers. Data written into the status
register does not alter the TO or PD flags. OperLabels
Bits
Function
C
0
C is set if the operation results in a carry during an addition operation or if a borrow does not take place during a subtraction operation; otherwise C is cleared. C
is also affected by a rotate through carry instruction.
AC
1
AC is set if the operation results in a carry out of the low nibbles in addition or no
borrow from the high nibble into the low nibble in subtraction; otherwise AC is
cleared.
Z
2
Z is set if the result of an arithmetic or logic operation is zero; otherwise Z is
cleared.
OV
3
OV is set if the operation results in a carry into the highest-order bit but not a
carry out of the highest-order bit, or vice versa; otherwise OV is cleared.
PD
4
PD is cleared by either a system power-up or executing the ²CLR WDT² instruction. PD is set by executing the ²HALT² instruction.
TO
5
TO is cleared by a system power-up or executing the ²CLR WDT² or ²HALT² instruction. TO is set by a WDT time-out.
¾
6
Undefined, read as ²0²
¾
7
Undefined, read as ²0²
Status register
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August 18, 1999
HT49C50
Once an interrupt subroutine is serviced, other
interrupts are all blocked (by clearing the EMI
bit). This scheme may prevent any further interrupt nesting. Other interrupt requests may
take place during this interval, but only the interrupt request flag will be recorded. If a certain interrupt requires servicing within the
service routine, the EMI bit and the corresponding bit of the INTC0 or of INTC1 may be set in
order to allow interrupt nesting. Once the stack is
Register
INTC0
(0BH)
INTC1
(1EH)
full, the interrupt request will not be acknowledged, even if the related interrupt is enabled,
until the SP is decremented. If immediate service
is desired, the stack should be prevented from becoming full.
All these interrupts can support a wake-up
function. As an interrupt is serviced, a control
transfer occurs by pushing the contents of the
PC onto the stack followed by a branch to a sub-
Bit No.
Label
Function
0
EMI
Control the master (global) interrupt
(1=enabled; 0=disabled)
1
EEI0
Control the external interrupt 0
(1=enabled; 0=disabled)
2
EEI1
Control the external interrupt 1
(1=enabled; 0=disabled)
3
ET0I
Control the timer/event counter 0 interrupt
(1=enabled; 0=disabled)
4
EIF0
External interrupt 0 request flag
(1=active; 0=inactive)
5
EIF1
External interrupt 1 request flag
(1=active; 0=inactive)
6
T0F
Internal timer/event counter 0 request flag
(1=active; 0=inactive)
7
¾
0
ET1I
Control the timer/event counter 1 interrupt
(1=enabled; 0=disabled)
1
ETBI
Control the time base interrupt
(1=enabled; 0:disabled)
2
ERTI
Control the real time clock interrupt
(1=enabled; 0:disabled)
3
¾
4
T1F
Internal timer/event counter 1 request flag
(1=active; 0=inactive)
5
TBF
Time base request flag
(1=active; 0=inactive)
6
RTF
Real time clock request flag
(1=active; 0=inactive)
7
¾
Unused bit, read as ²0²
Unused bit, read as ²0²
Unused bit, read as ²0²
INTC register
14
August 18, 1999
HT49C50
routine at the specified location in the ROM.
Only the contents of the PC is pushed onto the
stack. If the contents of the register or of the
status register (STATUS) is altered by the interrupt service program which corrupts the desired control sequence, the contents should be
saved in advance.
until the ²RETI² instruction is executed or the
EMI bit and the related interrupt control bit are
set both to 1 (if the stack is not full). To return
from the interrupt subroutine, ²RET² or ²RETI²
may be invoked. RETI sets the EMI bit and enables an interrupt service, but RET does not.
Interrupts occurring in the interval between
the rising edges of two consecutive T2 pulses
are serviced on the latter of the two T2 pulses if
the corresponding interrupts are enabled. In
the case of simultaneous requests, the priorities in the following table apply. These can be
masked by resetting the EMI bit.
External interrupts are triggered by a high to
low transition of INT0 or INT1, and the related
interrupt request flag (EIF0; bit 4 of INTC0,
EIF1; bit 5 of INTC0) is set as well. After the interrupt is enabled, the stack is not full, and the
external interrupt is active, a subroutine call to
location 04H or 08H occurs. The interrupt request flag (EIF0 or EIF1) and EMI bits are all
cleared to disable other interrupts.
No.
The internal timer/event counter 0 interrupt is
initialized by setting the timer/event counter 0
interrupt request flag (T0F; bit 6 of INTC0),
which is normally caused by a timer overflow.
After the interrupt is enabled, and the stack is
not full, and the T0F bit is set, a subroutine call
to location 0CH occurs. The related interrupt
request flag (T0F) is reset, and the EMI bit is
cleared to disable further interrupts. The
timer/event counter 1 is operated in the same
manner but its related interrupt request flag is
T1F (bit 4 of INTC1) and its subroutine call location is 10H.
Interrupt Source Priority Vector
a
External interrupt 0
1
04H
b
External interrupt 1
2
08H
c
Timer/event
counter 0 overflow
3
0CH
d
Timer/event
counter 1 overflow
4
10H
e
Time base
interrupt
5
14H
f
Real time clock
interrupt
6
18H
The timer/event counter 0 interrupt request
flag (T0F), external interrupt 1 request flag
(EIF1), external interrupt 0 request flag
(EIF0), enable timer/event counter 0 interrupt
bit (ET0I), enable external interrupt 1 bit
(EEI1), enable external interrupt 0 bit (EEI0),
and enable master interrupt bit (EMI) make up
of the Interrupt Control register 0 (INTC0)
which is located at 0BH in the RAM. The real
time clock interrupt request flag (RTF), time
base interrupt request flag (TBF), timer/event
counter 1 interrupt request flag (T1F), enable
real time clock interrupt bit (ERTI), and enable
time base interrupt bit (ETBI), enable
timer/event counter 1 interrupt bit (ET1I) on
the other hand, constitute the Interrupt Control register 1 (INTC1) which is located at 1EH
in the RAM. EMI, EEI0, EEI1, ET0I, ET1I,
ETBI, and ERTI are all used to control the enable/disable status of interrupts. These bits
prevent the requested interrupt from being ser-
The time base interrupt is initialized by setting
the time base interrupt request flag (TBF; bit 5
of INTC1), that is caused by a regular time base
signal. After the interrupt is enabled, and the
stack is not full, and the TBF bit is set, a subroutine call to location 14H occurs. The related
interrupt request flag (TBF) is reset and the
EMI bit is cleared to disable further interrupts.
The real time clock interrupt is initialized by
setting the real time clock interrupt request
flag (RTF; bit 6 of INTC1), that is caused by a
regular real time clock signal. After the interrupt is enabled, and the stack is not full, and
the RTF bit is set, a subroutine call to location
18H occurs. The related interrupt request flag
(RTF) is reset and the EMI bit is cleared to disable further interrupts.
During the execution of an interrupt subroutine,
other interrupt acknowledgments are all held
15
August 18, 1999
HT49C50
On the other hand, if the crystal oscillator is selected, a crystal across OSC1 and OSC2 is
needed to provide the feedback and phase shift
required for the oscillator, and no other external components are required. A resonator may
be connected between OSC1 and OSC2 to replace the crystal and to get a frequency reference, but two external capacitors in OSC1 and
OSC2 are required.
viced. Once the interrupt request flags (RTF,
TBF, T0F, T1F, EIF1, EIF0) are all set, they remain in the INTC1 or INTC0 respectively until
the interrupts are serviced or cleared by a software instruction.
It is recommended that a program not use the ²CALL
subroutine² within the interrupt subroutine. It¢s
because interrupts often occur in an unpredictable
manner or require to be serviced immediately in
some applications. At this time, if only one stack is
left, and enabling the interrupt is not well controlled, operation of the ²call² in the interrupt
subroutine may damage the original control sequence.
There is another oscillator circuit designed for
the real time clock. In this case, only the
32.768kHz crystal oscillator can be applied.
The crystal should be connected between OSC3
and OSC4, and two external capacitors along
with one external resistor are required for the
oscillator circuit in order to get a stable frequency.
Oscillator configuration
The HT49C50 provides two oscillator circuits
for system clocks, i.e., RC oscillator and crystal
oscillator, determined by mask option. No matter what type of oscillator is selected, the signal
is used for the system clock. The HALT mode
stops the system oscillator and ignores external
signal to conserve power.
The RTC oscillator circuit can be controlled to
oscillate quickly by setting the ²QOSC² bit (bit
4 of RTCC). It is recommended to turn on the
quick oscillating function upon power on, and
turn it off after 2 seconds.
Of the two oscillators, if the RC oscillator is
used, an external resistor between OSC1 and
VSS is required, and the range of the resistance
should be from 51kW to 1MW. The system clock,
divided by 4, is available on OSC2 with
pull-high resistor, which can be used to synchronize external logic. The RC oscillator provides the most cost effective solution. However,
the frequency of the oscillation may vary with
VDD, temperature, and the chip itself due to
process variations. It is therefore, not suitable
for timing sensitive operations where accurate
oscillator frequency is desired.
O S C 1
O S C 3
O S C 4
RTC oscillator
The WDT oscillator is a free running on-chip
RC oscillator, and no external components are
required. Although the system enters the
power down mode, the system clock stops, and
the WDT oscillator still works with a period of
approximately 78ms. The WDT oscillator can be
disabled by mask option to conserve power.
O S C 1
V D D
fS
O S C 2
Y S
/4
C r y s ta l O s c illa to r
O S C 2
R C
O s c illa to r
System oscillator
16
August 18, 1999
HT49C50
Watchdog timer - WDT
i.e., external reset (a low level to RES), software
instruction, and a ²HALT² instruction. There
are two types of software instructions; ²CLR
WDT² and the other set - ²CLR WDT1² and
²CLR WDT2². Of these two types of instruction,
only one type of instruction can be active at a
time depending on the mask option - ²CLR
WDT times selection option². If the ²CLR WDT²
is selected (i.e., CLR WDT times equal one), any
execution of the ²CLR WDT² instruction clears
the WDT. In the case that ²CLR WDT1² and
²CLR WDT2² are chosen (i.e., CLR WDT times
equal two), these two instructions have to be executed to clear the WDT; otherwise, the WDT
may reset the chip due to time-out.
The WDT clock source is implemented by a dedicated RC oscillator (WDT oscillator) or an instruction clock (system clock/4) or a real time
clock oscillator (RTC oscillator). The timer is
designed to prevent a software malfunction or
sequence from jumping to an unknown location
with unpredictable results. The WDT can be
disabled by mask option. But if the WDT is disabled, all executions related to the WDT lead to
no operation.
After the WDT clock source is selected, the
15
16
time-out period is fS/2 ~ fS/2 .
If the WDT clock source chooses the internal
WDT oscillator, the time-out period may vary
with temperature, VDD, and process variations.
On the other hand, if the clock source selects the
instruction clock and the ²halt² instruction is executed, WDT may stop counting and lose its protecting purpose, and the logic can only be
restarted by an external logic.
Multi-function timer
The HT49C50 provides a multi-function timer for
the WDT, time base and RTC but with different
time-out periods. The multi-function timer consists of a 7-stage divider and an 8-bit prescaler,
with the clock source coming from the WDT OSC
or RTC OSC or the instruction clock (i.e.., system
clock divided by 4). The multi-function timer also
provides a selectable frequency signal (ranges
2
8
from fS/2 to fS/2 ) for LCD driver circuits, and a
2
selectable frequency signal (ranges from fS/2 to
9
fS/2 ) for the buzzer output by mask option. It is
recommended to select a near 4kHz signal to
LCD driver circuits for proper display.
When the device operates in a noisy environment, using the on-chip RC oscillator (WDT
OSC) is strongly recommended, since the HALT
can stop the system clock.
The WDT overflow under normal operation
initializes a ²chip reset² and sets the status bit
²TO². In the HALT mode, the overflow
initializes a ²warm reset², and only the PC and
SP are reset to zero. To clear the contents of the
WDT, there are three methods to be adopted,
S y s te m
C lo c k /4
R T C
3 2 7 6 8 H z
O S C
M a s k
O p tio n
S e le c t
fS
D iv id e r
P r e s c a le r
C K
W D T
1 2 k H z
O S C
T
R
C K
T
R
T im e - o u t R e s e t
fS /2 15 ~ fS /2 16
W D T C le a r
17
August 18, 1999
HT49C50
Time base
The time base offers a periodic time-out period
to generate a regular internal interrupt. Its
12
15
time-out period ranges from fS/2 to fS/2 selected by mask option. If time base time-out occurs, the related interrupt request flag (TBF;
bit 5 of INTC1) is set. But if the interrupt is enabled, and the stack is not full, a subroutine call
to location 14H occurs. The time base time-out
signal also can be applied to be a clock source of
timer/event counter 1 for getting a longer
timer-out period.
RT2
RT1
RT0
RTC Clock Divided
Factor
0
0
0
2
0
0
1
2
0
1
0
2
0
1
1
2
1
0
0
2
1
0
1
2
1
1
0
2
1
1
1
2
Real time clock - RTC
The real time clock (RTC) is operated in the
same manner as the time base that is used to
supply a regular internal interrupt. Its
8
15
time-out period ranges from fS/2 to fS/2 by
software programming . Writing data to RT2,
RT1 and RT0 (bit2, 1, 0 of RTCC;09H) yields
various time-out periods. If the RTC time-out
occurs, the related interrupt request flag (RTF;
bit 6 of INTC1) is set. But if the interrupt is enabled, and the stack is not full, a subroutine call
to location 18H occurs. The real time clock
time-out signal also can be applied to be a clock
source of timer/event counter 0 for getting a
longer time-out period.
fs
11
12
13
14
15
Power down operation - HALT
· The system oscillator turns off but the WDT
oscillator keeps running (if the WDT oscillator or the real time clock is selected).
· The contents of the on-chip RAM and of the
registers remain unchanged.
· The WDT is cleared and start recounting (if
the WDT clock source is from the WDT oscillator or the real time clock oscillator).
P r e s c a le r
M a sk
O p tio n
M a s k O p tio n
2
8
T im e B a s e In te r r u p t
D r iv e r ( fS /2 ~ fS /2 )
2
9
10
The HALT mode is initialized by the ²HALT²
instruction and results in the following.
D iv id e r
L C D
8
9
(fS /2
B u z z e r (fS /2 ~ fS /2 )
1 2
1 5
~ fS /2 )
Time base
fS
D iv id e r
P r e s c a le r
R T 2
R T 1
R T 0
8 to 1
M u x .
1 2
1 5
fS /2 ~ fS /2
R T C In te rru p t
Real time clock
18
August 18, 1999
HT49C50
· All I/O ports maintain their original status.
To minimize power consumption, all the I/O
pins should be carefully managed before entering the HALT status.
· The PD flag is set but the TO flag is cleared.
· LCD driver is still running (if the WDT OSC
Reset
or RTC OSC is selected).
There are three ways in which reset may occur.
The system quits the HALT mode by an external
reset, an interrupt, an external falling edge signal on port A, or a WDT overflow. An external reset causes device initialization, and the WDT
overflow performs a ²warm reset². After examining the TO and PD flags, the reason for chip reset can be determined. The PD flag is cleared by
system power-up or by executing the ²CLR
WDT² instruction, and is set by executing the
²HALT² instruction. On the other hand, the TO
flag is set if WDT time-out occurs, and causes a
wake-up that only resets the PC (Program
Counter) and SP, and leaves the others at their
original state.
· RES is reset during normal operation
· RES is reset during HALT
· WDT time-out is reset during normal
operation
The WDT time-out during HALT differs from
other chip reset conditions, for it can perform a
²warm reset² that resets only the PC and SP
and leaves the other circuits at their original
state. Some registers remain unaffected during
any other reset conditions. Most registers are
reset to the ²initial condition² once the reset
conditions are met. Examining the PD and TO
flags, the program can distinguish between different ²chip resets².
The port A wake-up and interrupt methods can
be considered as a continuation of normal execution. Each bit in port A can be independently
selected to wake up the device by mask option.
Awakening from an I/O port stimulus, the program resumes execution of the next instruction. On the other hand, awakening from an
interrupt, two sequences may occur. If the related interrupt is disabled or the interrupt is
enabled but the stack is full, the program resumes execution at the next instruction. But if
the interrupt is enabled, and the stack is not
full, the regular interrupt response takes place.
V D D
R E S
Reset circuit
When an interrupt request flag is set before entering the ²halt² status, the system cannot be
awaken using that interrupt.
If wake-up events occur, it takes 1024 tSYS (system clock period) to resume normal operation.
In other words, a dummy period is inserted after the wake-up. If the wake-up results from an
interrupt acknowledgment, the actual interrupt subroutine execution is delayed by more
than one cycle. However, if the Wake-up results
in the next instruction execution, the execution
will be performed immediately after the
dummy period is finished.
TO
PD
RESET Conditions
0
0
RES reset during power-up
u
u
RES reset during normal
operation
0
1
RES Wake-up HALT
1
u
WDT time-out during normal
operation
1
1
WDT Wake-up HALT
Note: ²u² means ²unchanged²
19
August 18, 1999
HT49C50
To guarantee that the system oscillator is started
and stabilized, the SST (System Start-up Timer)
provides an extra-delay of 1024 system clock
pulses when the system awakes from the HALT
state or during power up. Awaking from the
HALT state or system power-up, the SST delay is
added.
V D D
R E S
C h ip
Reset timing chart
The functional unit chip reset status is shown
below.
000H
Interrupt
Disabled
Prescaler, Divider
Cleared
WDT, RTC, Time
base
Cleared. After master
reset, WDT starts
counting
Timer/event
counter
Off
Input/output ports
SP
S T
R e s e t
An extra SST delay is added during the
power-up period, and any wake-up from the
HALT may enable only the SST delay.
PC
tS
S S T T im e - o u t
H A L T
W a rm
W D T
E x te rn a l
R E S
O S C 1
R e s e t
W D T
T im e - o u t
R e s e t
C o ld
R e s e t
S S T
1 0 - b it R ip p le
C o u n te r
P o w e r - o n D e te c tio n
Reset configuration
Input mode
Points to the top of the
stack
20
August 18, 1999
HT49C50
The states of the registers are summarized below:
Register
Reset
(Power On)
WDT
Time-out
(Normal
Operation)
RES Reset
(Normal
Operation)
RES Reset
(HALT)
WDT
Time-out
(HALT)*
TMR0
xxxx xxxx
uuuu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
TMR0C
0000 1---
0000 1---
0000 1---
0000 1---
uuuu u---
TMR1
xxxx xxxx
uuuu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
TMR1C
0000 1---
0000 1---
0000 1---
0000 1---
uuuu u---
Program Counter
000H
000H
000H
000H
000H
MP0
xxxx xxxx
uuuu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
MP1
xxxx xxxx
uuuu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
ACC
xxxx xxxx
uuuu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
TBLP
xxxx xxxx
uuuu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
TBLH
-xxx xxxx
-uuu uuuu
-uuu uuuu
-uuu uuuu
-uuu uuuu
STATUS
--00 xxxx
--1u uuuu
--uu uuuu
--01 uuuu
--11 uuuu
INTC0
-000 0000
-000 0000
-000 0000
-000 0000
-uuu uuuu
INTC1
-000 -000
-000 -000
-000 -000
-000 -000
-uuu -uuu
RTCC
--00 0111
--00 0111
--00 0111
--00 0111
--uu uuuu
PA
1111 1111
1111 1111
1111 1111
1111 1111
uuuu uuuu
PB
1111 1111
1111 1111
1111 1111
1111 1111
uuuu uuuu
PC
---- 1111
---- 1111
---- 1111
---- 1111
---- uuuu
Notes: ²*² refers to warm reset
²u² means unchanged
²x² means unknown
21
August 18, 1999
HT49C50
timer/event counter control registers used to
define some options.
Timer/event counter
Two timer/event counters are implemented in
the HT49C50. Both of them contain an 8-bit
programmable count-up counter.
The TN0 and TN1 bits define the operation
mode. The event count mode is used to count external events, which means that the clock
source is from an external (TMR0, TMR1) pin.
The timer mode functions as a normal timer
with the clock source coming from the internal
selected clock source. Finally, the pulse width
measurement mode can be used to count the
high or low level duration of the external signal
(TMR0, TMR1), and the counting is based on
the internal selected clock source.
The timer/event count 0 clock source may come
from the system clock or system clock/4 or RTC
time-out signal or external source. System
clock source or system clock/4 is selected by
mask option.
The timer/event count 1 clock source may come
from TMR0 overflow or system clock or time
base time-out signal or system clock/4 or external source, and the three former clock source is
selected by mask option.
In the event count or timer mode, the timer/event
counter starts counting at the current contents in
the timer/event counter and ends at FFH. Once
an overflow occurs, the counter is reloaded from
the timer/event counter preload register, and
generates an interrupt request flag (T0F; bit 6 of
INTC0, T1F; bit 4 of INTC1).
The external clock input allows the user to
count external events, measure time intervals
or pulse widths, or to generate an accurate time
base.
The two timer/event counters are operated almost in the same manner, except the clock
source and related registers.
In the pulse width measurement mode with
the values of the TON and TE bits equal to
one, after the TMR0 (TMR1) has received a
transient from low to high (or high to low if
the TE bit is ²0²), it will start counting until
the TMR0 (TMR1) returns to the original
level and resets the TON. The measured result remains in the timer/event counter even
if the activated transient occurs again. In
other words, only one cycle measurement can
be made until the TON is set. The cycle measurement will re-function as long as it receives
There are two registers related to the
timer/event counter 0, i.e., TMR0 ([0DH]) and
TMR0C ([0EH]), and two registers related to
the timer/event counter 1, i.e., TMR1 ([10H],
and TMR1C ([11H]). There are also two physical registers are mapped to TMR0 (TMR1) location; writing TMR0 (TMR1) places the starting
value in the timer/event counter preload register, while reading it yields the contents of the
timer/event counter. TMR0C and TMR1C are
S y s te m
S y s te m
C lo c k
C lo c k /4
M a s k
O p tio n
S e le c t
M
U
X
D a ta b u s
R T C O u t
T N 1
T N 0
T N 2
T M R 0
T im e r /e v e n t c o u n te r 0
P r e lo a d R e g is te r
R e lo a d
T E
T N 1
T N 0
T O N
T im e r /e v e n t
c o u n te r 0
P u ls e W id th
M e a s u re m e n t
M o d e C o n tro l
T
O v e r flo w
T o In te rru p t
Q
P F D 0
P A 3 D a ta C T R L
Timer/event counter 0
22
August 18, 1999
HT49C50
Label
(TMR0C)
Bits
Function
0~2 Unused bits, read as ²0²
¾
TE
3
To define the TMR0 active edge of timer/event counter
(0=active on low to high; 1=active on high to low)
TON
4
To enable/disable timer counting
(0=disabled; 1=enabled)
TN2
5
2 to 1 multiplexer control inputs to select the timer/event counter clock source
(0=RTC outputs; 1= system clock or system clock/4)
6
7
To define the operating mode (TN1, TN0)
01= Event count mode (External clock)
10= Timer mode (Internal clock)
11= Pulse Width measurement mode (External clock)
00= Unused
TN0
TN1
TMR0C register
instructions. The overflow of the timer/event
counter 0/1 is one of the wake-up sources and
can also be applied to a PFD (Programmable
Frequency Divider) output at PA3 by mask option. Only one PFD (PFD0 or PFD1) can be applied to PA3 by mask option . No matter what the
operation mode is, writing a 0 to ET0I or ET1I
disables the related interrupt service. When the
PFD function is selected, executing ²CLR [PA].3²
instruction to enable PFD output and executing
²SET [PA].3² instruction to disable PFD output.
further transient pulse. In this operation mode,
the timer/event counter begins counting according not to the logic level but to the transient
edges. In the case of counter overflows, the counter is reloaded from the timer/event counter
preload register and issues an interrupt request,
as in the other two modes, i.e., event and timer
modes.
To enable the counting operation, the Timer ON
bit (TON; bit 4 of TMR0C or TMR1C) should be
set to 1. In the pulse width measurement mode,
the TON is automatically cleared after the
measurement cycle is completed. But in the
other two modes, the TON can only be reset by
T M R 0 O v e r flo w
S y s te m
M a s k
O p tio n
S e le c t
C lo c k
T im e B a s e O u t
S y s te m
In the case of timer/event counter OFF
condition, writing data to the timer/event counter
preload register also reloads that data to the
M
U
X
D a ta b u s
C lo c k /4
T N 1
T N 0
T N 2
T M R 1
T im e r /e v e n t c o u n te r 1
P r e lo a d R e g is te r
R e lo a d
T E
T N 1
T N 0
T O N
O v e r flo w
T o In te rru p t
T im e r /e v e n t
c o u n te r 1
P u ls e W id th
M e a s u re m e n t
M o d e C o n tro l
T
Q
P F D 1
P A 3 D a ta C T R L
Timer/event counter 1
23
August 18, 1999
HT49C50
Label
(TMR1C)
Bits
¾
0~2
Function
Unused bits, read as ²0²
TE
3
To define the TMR1 active edge of timer/event counter
(0= active on low to high; 1= active on high to low)
TON
4
To enable/disable timer counting
(0= disabled; 1= enabled)
TN2
5
2 to 1 multiplexer control inputs to select the timer/event counter clock source
(0= mask option clock source; 1= system clock/4)
7
6
To define the operating mode
01= Event count mode (External clock)
10= Timer mode (Internal clock)
11= Pulse Width measurement mode (External clock)
00= Unused
TN1
TN0
TMR1C register
START:
timer/ event counter. But if the timer/event
counter is turn on, data written to the
timer/event counter is kept only in the
timer/event counter preload register. The
timer/event counter still continues its operation until an overflow occurs.
mov
mov
a, 09h ; Set ET0I&EMI bits to
intc0, a ; enable timer 0 and
; global interrupt
mov a, 01h ; Set ET1I bit to enable
mov intc1, a ; timer 1 interrupt
When the timer/event counter (reading
TMR0/TMR1) is read, the clock is blocked to
avoid errors. As this may results in a counting
error, blocking of the clock should be taken into
account by the programmer.
mov a, 80h ; Set operating mode as
mov tmr1c, a ; timer mode and select mask
; option clock source
mov a, 0a0h ; Set operating mode as timer
mov tmr0c, a ; mode and select system
; clock/4
It is strongly recommended to load a desired
value into the TMR0/TMR1 register first, then
turn on the related timer/event counter for
proper operation. Because the initial value of
TMR0/TMR1 is unknown.
set tmr1c.4 ; Enable then disable timer 1
clr tmr1c.4 ; for the first time
Due to the timer/event scheme, the programmer should pay special attention on the instruction to enable then disable the timer for the
first time, whenever there is a need to use the
timer/event function, to avoid unpredicatable
result. After this procedure, the timer/event
function can be operated normally. The example given below, using two 8-bit width Timer¢s
(timer 0 ;timer 1) cascade into 16-bit width.
mov
mov
mov
mov
a, 00h
tmr0, a
a, 00h
tmr1, a
set tmr0c.4
set tmr1c.4
; Load a desired value into
; the TMR0/TMR1 register
;
;
; Normal operating
;
END
24
August 18, 1999
HT49C50
Input/output ports
There are a 12-bit bidirectional input/output
port, an 8-bit input port in the HT49C50, labeled
PA, PB and PC which are mapped to [12H],
[14H] and [16H] of the RAM, respectively.
PA0~PA3 can be configured as CMOS (output)
or NMOS (input/output) with or without
pull-high resistor by mask option. PA4~PA7 are
always pull-high and NMOS (input/output). If you
choose NMOS (input), each bit on the port
(PA0~PA7) can be configured as a wake-up input.
PB can only be used for input operation, and each
bit on the port can be configured with pull-high resistor. PC can be configured as CMOS output or
NMOS input/output with or without pull-high resistor by mask option. All the port for the input operation (PA, PB and PC), these ports are
non-latched, that is, the inputs should be ready at
the T2 rising edge of the instruction ²MOV A, [m]²
(m=12H or 14H). For PA, PC output operation, all
data are latched and remain unchanged until the
outputlatch is rewritten.
When the PA and PC structures are open drain
NMOS type, it should be noted that, before
reading data from the pads, a ²1² should be
written to the related bits to disable the NMOS
device. That is executing first the instruction
²SET [m].i² (i=0~7 for PA) to disable related
NMOS device, and then ²MOV A, [m]² to get
stable data.
After chip reset, these input lines remain at the
high level or are left floating (by mask option).
Each bit of these output latches can be set or
cleared by the ²SET [m].i² and ²CLR [m].i²
(m=12H or 16H) instructions.
Some instructions first input data and then follow the output operations. For example, ²SET
[m].i², ²CLR [m].i², ²CPL [m]², ²CPLA [m]² read
the entire port states into the CPU, execute the
defined operations (bit-operation), and then
write the results back to the latches or to the accumulator.
V D D
V D D
D a ta b u s
W r ite
D
M a s k
o p tio n
(P A 0 ~
P A 3 , P C )
Q
C K
S
Q
P C
W e a k
P u ll- u p
M a s k o p tio n
(P A 0 ~ P A 3 , P C )
P A 0 ~ P A 7
P B 0 ~ P B 7
P C 0 ~ P C 3
C h ip R e s e t
R e a d I/O
S y s te m
W a k e - u p ( P A o n ly )
M a s k o p tio n
Input/output ports
25
August 18, 1999
HT49C50
LCD display memory
memory can be read and written to only by indirect addressing mode using MP1. When data is
written into the display data area, it is automatically read by the LCD driver which then
generates the corresponding LCD driving signals. To turn the display on or off, a ²1² or a ²0²
is written to the corresponding bit of the display
memory, respectively. The figure illustrates the
mapping between the display memory and LCD
pattern for the HT49C50.
The HT49C50 provides an area of embedded
data memory for LCD display. This area is located from 40H to 60H of the RAM at Bank 1.
Bank pointer (BP; located at 04H of the RAM) is
the switch between the RAM and the LCD display memory. When the BP is set as ²1², any
data written into 40H~60H will effect the LCD
display. When the BP is cleared to ²0², any data
written into 40H~60H means to access the general purpose data memory. The LCD display
C O M
4 0 H
4 1 H
4 2 H
4 3 H
5 E H
5 F H
6 0 H
B it
0
0
1
1
2
2
3
3
S E G M E N T
0
1
2
3
3 0
3 1
3 2
Display memory
26
August 18, 1999
HT49C50
LCD driver output
Buzzer
The output number of the HT49C50 LCD driver
can be 33´2 or 33´3 or 32´4 by mask option (i.e.,
1/2 duty or 1/3 duty or 1/4 duty). The bias type of
LCD driver can be ²R² type or ²C² type. If the ²R²
bias type is selected, no external capacitor is required. If the ²C² bias type is selected, a capacitor
mounted between C1 and C2 pins is needed. The
bias voltage of LCD driver can be 1/2 bias or 1/3
bias by mask option. If 1/2 bias is selected, a capacitor mounted between V2 pin and ground is
required. If 1/3 bias is selected, two capacitors are
needed for V1 and V2 pins. Refer to application
diagram.
HT49C50 provides a pair of buzzer output BZ
and BZ, which share pins with PA0 and PA1 respectively, ad determined by mask option. Its
output frequency can be selected by mask option.
When the buzzer function is selected, setting
the PA.0 and PA.1 ²0² simultaneously, will enables the buzzer output and sets the PA.0 ²1² to
disable the buzzer output.
D u r in g a R e s e t P u ls e :
C O M 0 ,C O M 1 ,C O M 2
A ll L C D d r iv e r o u tp u ts
N o r m a l O p e r a tio n M o d e :
C O M 0
C O M 1
C O M 2
L C D s e g m e n ts o n C O M
0 ,1 ,2 s id e s b e in g u n lit
O n ly L C D s e g m e n ts o n
C O M 0 s id e b e in g lit
O n ly L C D s e g m e n ts o n
C O M 1 s id e b e in g lit
O n ly L C D s e g m e n ts o n
C O M 2 s id e b e in g lit
L C D s e g m e n ts o n
C O M 0 ,1 s id e s b e in g lit
L C D s e g m e n ts o n
C O M 0 ,2 s id e s b e in g lit
L C D s e g m e n ts o n
C O M 1 ,2 s id e s b e in g lit
L C D s e g m e n ts o n
C O M 0 ,1 ,2 s id e s b e in g lit
H a lt M o d e :
C O M 0 ,C O M 1 ,C O M 2
A ll L C D d r iv e r o u tp u ts
V L
1 /2
V S
V L
1 /2
V S
C D
V L
1 /2
V S
V L
1 /2
V S
V L
1 /2
V S
V L
1 /2
V S
V L
1 /2
V S
V L
1 /2
V S
V L
1 /2
V S
V L
1 /2
V S
V L
1 /2
V S
V L
1 /2
V S
V L
1 /2
V S
C D
V L
1 /2
V S
V L
1 /2
V S
C D
S
C D
S
S
C D
S
C D
S
C D
S
C D
S
C D
S
C D
S
C D
S
C D
S
C D
S
C D
S
S
C D
S
V L C D
V L C D
V L C D
V L C D
V L C D
V L C D
V L C D
V L C D
V L C D
V L C D
V L C D
V L C D
V L C D
V L C D
V L C D
LCD driver output (1/3 duty, 1/2 bias, R/C type)
27
August 18, 1999
HT49C50
3 /2 V L C D
V L C D
1 /2 V L C D
C O M 0
V S S
3 /2 V L C D
V L C D
1 /2 V L C D
C O M 1
V S S
3 /2 V L C D
V L C D
1 /2 V L C D
C O M 2
V S S
3 /2 V L C D
V L C D
C O M 3
1 /2 V L C D
V S S
3 /2 V L C D
V L C D
L C D s e g m e n ts O N
C O M 2 s id e lig h te d
1 /2 V L C D
V S S
LCD driver output (1/4 duty, 1/3 bias, C type)
28
August 18, 1999
HT49C50
Register Bit No. Label Read/Write Reset
RTCC
(09H)
Function
0~2
RT0
RT1
RT2
R/W
0
8 to 1 multiplexer control inputs to select the
real time clock prescaler output
3
¾
¾
¾
Unused bits, this bit must dear to ²0²
4
QOSC
R/W
0
Control the RTC OSC to oscillate quickly
²0² enable
²1² disable
5~7
¾
¾
¾
Unused bits, read as ²0²
RTCC register
Mask option
The following shows 18 kinds of mask options
in the HT49C50. All these options should be de-
fined in order to ensure proper system functioning.
No.
Mask Option
1
OSC type selection. This option is to decide if an RC or Crystal oscillator is chosen as system clock.
2
WDT Clock source selection. RTC and Time Base. There are three types of selection: system clock/4 or RTC OSC or WDT OSC.
3
WDT enable/disable selection. WDT can be enabled or disabled by mask option.
4
CLR WDT times selection. This option defines how to clear the WDT by instruction. ²One
time² means that the ²CLR WDT² can clear the WDT. ²Two times² means only if both of
the ²CLR WDT1² and ²CLR WDT2² have been executed, the WDT can be cleared.
5
Time Base time-out period selection. The Time Base time-out period ranges from
12
15
clock/2 to clock/2 . ²Clock² means the clock source selected by mask option.
6
uzzer output frequency selection. There are eight types of frequency signals for buzzer
2
9
output: Clock/2 ~Clock/2 . ²Clock² means the clock source selected by mask option.
7
Wake-up selection. This option defines the wake-up capability. External I/O pins (PA
only) all have the capability to wake-up the chip from a HALT by a falling edge.
8
Pull-high selection. This option is to decide whether the pull-high resistance is visible or
not on the PA0~PA3 and PC. (PB and PA4~PA7 are always pull-high)
9
PA0~PA3 and PC CMOS or NMOS selection.
The structure of PA0~PA3 and PC each 4 bits can be selected as CMOS or NMOS individually. When the CMOS is selected, the related pins only can be used for output operations. When the NMOS is selected, the related pins can be used for input or output
operations. (PA4~PA7 are always NMOS)
29
August 18, 1999
HT49C50
No.
Mask Option
10
Clock source selection of timer/event counter 0. There are two types of selection: system
clock or system clock/4.
11
Clock source selection of timer/event counter 1. There are three types of selection: TMR0
overflow, system clock or Time Base overflow.
12
I/O pins share with other functions selection.
PA0/BZ, PA1/BZ: PA0 and PA1 can be set as I/O pins or buzzer outputs.
PA3/PFD: PA3 can be set as I/O pins or PFD output.
13
LCD common selection. There are three types of selection: 2 common (1/2 duty) or 3 common (1/3 duty) or 4 common (1/4 duty). If the 4 common is selected, the segment output
pin ²SEG32² will be set as a common output.
14
LCD bias power supply selection.
There are two types of selection: 1/2 bias or 1/3 bias.
15
LCD bias type selection.
This option is to decide what kind of bias is selected, R type or C type.
16
LCD driver clock selection. There are seven types of frequency signals for the LCD driver
2
8
circuits: fS/2 ~fS/2 . ²fS² means the clock source selection by mask option.
17
PFD selection.
If PA3 is set as PFD output, there are two types of selection; One is PFD0 as the PFD output, the other is PFD1 as the PFD output. PFD0, PFD1 are the timer overflow signals of
the timer/event counter 0, timer/event counter 1 respectively.
30
August 18, 1999
HT49C50
Application Circuits
R C o s c illa to r a p p lic a tio n
C r y s ta l o s c illa to r a p p lic a tio n
O S C 1
O S C 1
S E G 0 ~ 3 1
C O M 0 ~ 3
V D D
L C D
P A N E L
S E G 0 ~ 3 1
C O M 0 ~ 3
L C D
P A N E L
O S C 2
fS
Y S
/4
V L C D
O S C 2
L C D P o w e r
S u p p ly
V L C D
V D D
L C D P o w e r
S u p p ly
V D D
C 1
C 1
0 .1 m F
R E S
C 2
R E S
O S C 3
H T 4 9 C 5 0
V 1
V 2
H T 4 9 C 5 0
0 .1 m F
O S C 3
0 .1 m F
0 .1 m F
C 2
V 1
V 2
0 .1 m F
0 .1 m F
O S C 4
O S C 4
IN T 0
IN T 1
T M R 0
T M R 1
P A 0 ~ P A 7
IN T 0
IN T 1
P B 0 ~ P B 7
P A 0 ~ P A 7
P B 0 ~ P B 7
T M R 0
P C 0 ~ P C 3
T M R 1
31
P C 0 ~ P C 3
August 18, 1999
HT49C50
Instruction Set Summary
Mnemonic
Description
Flag Affected
Add data memory to ACC
Add ACC to data memory
Add immediate data to ACC
Add data memory to ACC with carry
Add ACC to register with carry
Subtract immediate data from ACC
Subtract data memory from ACC
Subtract data memory from ACC with result in data memory
Subtract data memory from ACC with carry
Subtract data memory from ACC with carry with result in
data memory
Decimal adjust ACC for addition with result in data memory
Z,C,AC,OV
Z,C,AC,OV
Z,C,AC,OV
Z,C,AC,OV
Z,C,AC,OV
Z,C,AC,OV
Z,C,AC,OV
Z,C,AC,OV
Z,C,AC,OV
Z,C,AC,OV
Arithmetic
ADD A,[m]
ADDM A,[m]
ADD A,x
ADC A,[m]
ADCM A,[m]
SUB A,x
SUB A,[m]
SUBM A,[m]
SBC A,[m]
SBCM A,[m]
DAA [m]
C
Logic Operation
AND A,[m]
OR A,[m]
XOR A,[m]
ANDM A,[m]
ORM A,[m]
XORM A,[m]
AND A,x
OR A,x
XOR A,x
CPL [m]
CPLA [m]
AND data memory to ACC
OR data memory to ACC
Exclusive-OR data memory to ACC
AND ACC to data memory
OR ACC to data memory
Exclusive-OR ACC to data memory
AND immediate data to ACC
OR immediate data to ACC
Exclusive-OR immediate data to ACC
Complement data memory
Complement data memory with result in ACC
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
Increment data memory with result in ACC
Increment data memory
Decrement data memory with result in ACC
Decrement data memory
Z
Z
Z
Z
Increment
and
Decrement
INCA [m]
INC [m]
DECA [m]
DEC [m]
32
August 18, 1999
HT49C50
Mnemonic
Description
Flag Affected
Rotate data memory right with result in ACC
Rotate data memory right
Rotate data memory right through carry with result in ACC
Rotate data memory right through carry
Rotate data memory left with result in ACC
Rotate data memory left
Rotate data memory left through carry with result in ACC
Rotate data memory left through carry
None
None
C
C
None
None
C
C
Rotate
RRA [m]
RR [m]
RRCA [m]
RRC [m]
RLA [m]
RL [m]
RLCA [m]
RLC [m]
Data Move
MOV A,[m]
MOV [m],A
MOV A,x
Move data memory to ACC
Move ACC to data memory
Move immediate data to ACC
None**
None
None
Bit Operation
CLR [m].i
SET [m].i
Clear bit of data memory
Set bit of data memory
None
None
Jump unconditionally
Skip if data memory is zero
Skip if data memory is zero with data movement to ACC
Skip if bit i of data memory is zero
Skip if bit i of data memory is not zero
Skip if increment data memory is zero
Skip if decrement data memory is zero
Skip if increment data memory is zero with result in ACC
Skip if decrement data memory is zero with result in ACC
Subroutine call
Return from subroutine
Return from subroutine and load immediate data to ACC
Return from interrupt
None
None
None
None
None
None
None
None
None
None
None
None
None
Read ROM code (current page) to data memory and TBLH
Read ROM code (last page) to data memory and TBLH
None
None
Branch
JMP addr
SZ [m]
SZA [m]
SZ [m].i
SNZ [m].i
SIZ [m]
SDZ [m]
SIZA [m]
SDZA [m]
CALL addr
RET
RET A,x
RETI
Table Read
TABRDC [m]
TABRDL [m]
33
August 18, 1999
HT49C50
Mnemonic
Description
Flag Affected
Miscellaneous
NOP
CLR [m]
SET [m]
CLR WDT
CLR WDT1
CLR WDT2
SWAP [m]
SWAPA [m]
HALT
No operation
Clear data memory
Set data memory
Clear Watchdog timer
Pre-clear Watchdog timer
Pre-clear Watchdog timer
Swap nibbles of data memory
Swap nibbles of data memory with result in ACC
Enter power down mode
None
None
None
TO,PD
TO*,PD*
TO*,PD*
None
None
TO,PD
Notes: x: 8-bit immediate data
m: 7-bit data memory address
A: accumulator
i: 0~7 number of bits
addr: 10-bit program memory address
Ö: Flag(s) is affected
-: Flag(s) is not affected
*: Flag(s) may be affected by the execution status
**: For the old version of the E.V. chip, the zero flag (Z) can be affected by executing the
MOV A,[M] instruction.
For the new version of the E.V. chip, the zero flag cannot be changed by executing the
MOV A,[M] instruction.
34
August 18, 1999
HT49C50
Instruction Definition
ADC A,[m]
Add data memory and carry to the accumulator
Description
The contents of the specified data memory, accumulator and the carry flag
are added simultaneously, leaving the result in the accumulator.
Operation
ACC ¬ ACC+[m]+C
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
Ö
Ö
Ö
Ö
ADCM A,[m]
Add the accumulator and carry to data memory
Description
The contents of the specified data memory, accumulator and the carry flag
are added simultaneously, leaving the result in the specified data memory.
Operation
[m] ¬ ACC+[m]+C
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
Ö
Ö
Ö
Ö
ADD A,[m]
Add data memory to the accumulator
Description
The contents of the specified data memory and the accumulator are added.
The result is stored in the accumulator.
Operation
ACC ¬ ACC+[m]
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
Ö
Ö
Ö
Ö
ADD A,x
Add immediate data to the accumulator
Description
The contents of the accumulator and the specified data are added, leaving
the result in the accumulator.
Operation
ACC ¬ ACC+x
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
Ö
Ö
Ö
Ö
35
August 18, 1999
HT49C50
ADDM A,[m]
Add the accumulator to the data memory
Description
The contents of the specified data memory and the accumulator are added.
The result is stored in the data memory.
Operation
[m] ¬ ACC+[m]
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
Ö
Ö
Ö
Ö
AND A,[m]
Logical AND accumulator with data memory
Description
Data in the accumulator and the specified data memory perform a bitwise
logical_AND operation. The result is stored in the accumulator.
Operation
ACC ¬ ACC ²AND² [m]
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
Ö
¾
¾
AND A,x
Logical AND immediate data to the accumulator
Description
Data in the accumulator and the specified data perform a bitwise logical_AND operation. The result is stored in the accumulator.
Operation
ACC ¬ ACC ²AND² x
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
Ö
¾
¾
ANDM A,[m]
Logical AND data memory with the accumulator
Description
Data in the specified data memory and the accumulator perform a bitwise
logical_AND operation. The result is stored in the data memory.
Operation
[m] ¬ ACC ²AND² [m]
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
Ö
¾
¾
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August 18, 1999
HT49C50
CALL addr
Subroutine call
Description
The instruction unconditionally calls a subroutine located at the indicated
address. The program counter increments once to obtain the address of the
next instruction, and pushes this onto the stack. The indicated address is
then loaded. Program execution continues with the instruction at this address.
Operation
Stack ¬ PC+1
PC ¬ addr
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
¾
CLR [m]
Clear data memory
Description
The contents of the specified data memory are cleared to zero.
Operation
[m] ¬ 00H
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
¾
CLR [m].i
Clear bit of data memory
Description
The bit i of the specified data memory is cleared to zero.
Operation
[m].i ¬ 0
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
¾
CLR WDT
Clear watchdog timer
Description
The WDT is cleared (re-counting from zero). The power down bit (PD) and
time-out bit (TO) are cleared.
Operation
WDT ¬ 00H
PD and TO ¬ 0
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
0
0
¾
¾
¾
¾
37
August 18, 1999
HT49C50
CLR WDT1
Preclear watchdog timer
Description
The TD, PD flags and WDT are all cleared (re-counting from zero), if the
other preclear WDT instruction has been executed. Only execution of this instruction without the other preclear instruction sets the indicated flag which
implies that this instruction has been executed and the TO and PD flags remain unchanged.
Operation
WDT ¬ 00H*
PD and TO ¬ 0*
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
0*
0*
¾
¾
¾
¾
CLR WDT2
Preclear watchdog timer
Description
The TO, PD flags and WDT are all cleared (re-counting from zero), if the
other preclear WDT instruction has been executed. Only execution of this instruction without the other preclear instruction sets the indicated flag which
implies that this instruction has been executed and the TO and PD flags remain unchanged.
Operation
WDT ¬ 00H*
PD and TO ¬ 0*
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
0*
0*
¾
¾
¾
¾
CPL [m]
Complement data memory
Description
Each bit of the specified data memory is logically complemented (1¢s complement). Bits which previously contained a one are changed to zero and
vice-versa.
Operation
[m] ¬ [m]
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
Ö
¾
¾
38
August 18, 1999
HT49C50
CPLA [m]
Complement data memory and place result in the accumulator
Description
Each bit of the specified data memory is logically complemented (1¢s complement). Bits which previously contained a one are changed to zero and
vice-versa. The complemented result is stored in the accumulator and the
contents of the data memory remain unchanged.
Operation
ACC ¬ [m]
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
Ö
¾
¾
DAA [m]
Decimal-Adjust accumulator for addition
Description
The accumulator value is adjusted to the BCD (Binary Code Decimal) code.
The accumulator is divided into two nibbles. Each nibble is adjusted to the
BCD code and an internal carry (AC1) will be done if the low nibble of the accumulator is greater than 9. The BCD adjustment is done by adding 6 to the
original value if the original value is greater than 9 or a carry (AC or C) is set;
otherwise the original value remains unchanged. The result is stored in the
data memory and only the carry flag (C) may be affected.
Operation
If ACC.3~ACC.0 >9 or AC=1
then [m].3~[m].0 ¬ (ACC.3~ACC.0)+6, AC1=AC
else [m].3~[m].0) ¬ (ACC.3~ACC.0), AC1=0
and
If ACC.7~ACC.4+AC1 >9 or C=1
then [m].7~[m].4 ¬ ACC.7~ACC.4+6+AC1,C=1
else [m].7~[m].4 ¬ ACC.7~ACC.4+AC1,C=C
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
Ö
DEC [m]
Decrement data memory
Description
Data in the specified data memory is decremented by one.
Operation
[m] ¬ [m]-1
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
Ö
¾
¾
39
August 18, 1999
HT49C50
DECA [m]
Decrement data memory and place result in the accumulator
Description
Data in the specified data memory is decremented by one, leaving the result
in the accumulator. The contents of the data memory remain unchanged.
Operation
ACC ¬ [m]-1
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
Ö
¾
¾
HALT
Enter power down mode
Description
This instruction stops program execution and turns off the system clock. The
contents of the RAM and registers are retained. The WDT and prescaler are
cleared. The power down bit (PD) is set and the WDT time-out bit (TO) is
cleared.
Operation
PC ¬ PC+1
PD ¬ 1
TO ¬ 0
Affected flag(s)
INC [m]
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
0
1
¾
¾
¾
¾
Increment data memory
Description
Data in the specified data memory is incremented by one.
Operation
[m] ¬ [m]+1
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
Ö
¾
¾
INCA [m]
Increment data memory and place result in the accumulator
Description
Data in the specified data memory is incremented by one, leaving the result
in the accumulator. The contents of the data memory remain unchanged.
Operation
ACC ¬ [m]+1
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
Ö
¾
¾
40
August 18, 1999
HT49C50
JMP addr
Directly jump
Description
The contents of the program counter are replaced with the directly-specified
address unconditionally, and control is passed to this destination.
Operation
PC ¬ addr
Affected flag(s)
MOV A,[m]
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
¾
Move data memory to the accumulator
Description
The contents of the specified data memory are copied to the accumulator.
Operation
ACC ¬ [m]
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
¾
MOV A,x
Move immediate data to the accumulator
Description
The 8-bit data specified by the code is loaded into the accumulator.
Operation
ACC ¬ x
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
¾
MOV [m],A
Move the accumulator to data memory
Description
The contents of the accumulator are copied to the specified data memory (one
of the data memories).
Operation
[m] ¬ ACC
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
¾
NOP
No operation
Description
No operation is performed. Execution continues with the next instruction.
Operation
PC ¬ PC+1
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
¾
41
August 18, 1999
HT49C50
OR A,[m]
Logical OR accumulator with data memory
Description
Data in the accumulator and the specified data memory (one of the data
memories) perform a bitwise logical_OR operation. The result is stored in
the accumulator.
Operation
ACC ¬ ACC ²OR² [m]
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
Ö
¾
¾
OR A,x
Logical OR immediate data to the accumulator
Description
Data in the accumulator and the specified data perform a bitwise logical_OR
operation. The result is stored in the accumulator.
Operation
ACC ¬ ACC ²OR² x
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
Ö
¾
¾
ORM A,[m]
Logical OR data memory with the accumulator
Description
Data in the data memory (one of the data memories) and the accumulator
perform a bitwise logical_OR operation. The result is stored in the data
memory.
Operation
[m] ¬ ACC ²OR² [m]
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
Ö
¾
¾
RET
Return from subroutine
Description
The program counter is restored from the stack. This is a two-cycle instruction.
Operation
PC ¬ Stack
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
¾
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August 18, 1999
HT49C50
RET A,x
Return and place immediate data in the accumulator
Description
The program counter is restored from the stack and the accumulator loaded
with the specified 8-bit immediate data.
Operation
PC ¬ Stack
ACC ¬ x
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
¾
RETI
Return from interrupt
Description
The program counter is restored from the stack, and interrupts are enabled
by setting the EMI bit. EMI is the enable master (global) interrupt bit (bit 0;
register INTC).
Operation
PC ¬ Stack
EMI ¬ 1
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
¾
RL [m]
Rotate data memory left
Description
The contents of the specified data memory are rotated one bit left with bit 7
rotated into bit 0.
Operation
[m].(i+1) ¬ [m].i; [m].i:bit i of the data memory (i=0~6)
[m].0 ¬ [m].7
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
¾
RLA [m]
Rotate data memory left and place result in the accumulator
Description
Data in the specified data memory is rotated one bit left with bit 7 rotated
into bit 0, leaving the rotated result in the accumulator. The contents of the
data memory remain unchanged.
Operation
ACC.(i+1) ¬ [m].i; [m].i:bit i of the data memory (i=0~6)
ACC.0 ¬ [m].7
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
¾
43
August 18, 1999
HT49C50
RLC [m]
Rotate data memory left through carry
Description
The contents of the specified data memory and the carry flag are rotated one
bit left. Bit 7 replaces the carry bit; the original carry flag is rotated into the
bit 0 position.
Operation
[m].(i+1) ¬ [m].i; [m].i:bit i of the data memory (i=0~6)
[m].0 ¬ C
C ¬ [m].7
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
Ö
RLCA [m]
Rotate left through carry and place result in the accumulator
Description
Data in the specified data memory and the carry flag are rotated one bit left.
Bit 7 replaces the carry bit and the original carry flag is rotated into bit 0 position. The rotated result is stored in the accumulator but the contents of the
data memory remain unchanged.
Operation
ACC.(i+1) ¬ [m].i; [m].i:bit i of the data memory (i=0~6)
ACC.0 ¬ C
C ¬ [m].7
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
Ö
RR [m]
Rotate data memory right
Description
The contents of the specified data memory are rotated one bit right with bit 0
rotated to bit 7.
Operation
[m].i ¬ [m].(i+1); [m].i:bit i of the data memory (i=0~6)
[m].7 ¬ [m].0
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
¾
44
August 18, 1999
HT49C50
RRA [m]
Rotate right-place result in the accumulator
Description
Data in the specified data memory is rotated one bit right with bit 0 rotated
into bit 7, leaving the rotated result in the accumulator. The contents of the
data memory remain unchanged.
Operation
ACC.(i) ¬ [m].(i+1); [m].i:bit i of the data memory (i=0~6)
ACC.7 ¬ [m].0
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
¾
RRC [m]
Rotate data memory right through carry
Description
The contents of the specified data memory and the carry flag are together rotated one bit right. Bit 0 replaces the carry bit; the original carry flag is rotated into the bit 7 position.
Operation
[m].i ¬ [m].(i+1); [m].i:bit i of the data memory (i=0~6)
[m].7 ¬ C
C ¬ [m].0
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
Ö
RRCA [m]
Rotate right through carry-place result in the accumulator
Description
Data of the specified data memory and the carry flag are rotated one bit
right. Bit 0 replaces the carry bit and the original carry flag is rotated into
the bit 7 position. The rotated result is stored in the accumulator. The contents of the data memory remain unchanged.
Operation
ACC.i ¬ [m].(i+1); [m].i:bit i of the data memory (i=0~6)
ACC.7 ¬ C
C ¬ [m].0
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
Ö
45
August 18, 1999
HT49C50
SBC A,[m]
Subtract data memory and carry from the accumulator
Description
The contents of the specified data memory and the complement of the carry flag
aresubtractedfromtheaccumulator,leaving the result in theaccumulator.
Operation
ACC ¬ ACC+[m]+C
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
Ö
Ö
Ö
Ö
SBCM A,[m]
Subtract data memory and carry from the accumulator
Description
The contents of the specified data memory and the complement of the carry
flag are subtracted from the accumulator, leaving the result in the data
memory.
Operation
[m] ¬ ACC+[m]+C
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
Ö
Ö
Ö
Ö
SDZ [m]
Skip if decrement data memory is zero
Description
The contents of the specified data memory are decremented by one. If the result is zero, the next instruction is skipped. If the result is zero, the following
instruction, fetched during the current instruction execution, is discarded
and a dummy cycle is replaced to get the proper instruction (two cycles). Otherwise proceed with the next instruction (one cycle).
Operation
Skip if ([m]-1)=0, [m] ¬ ([m]-1)
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
¾
SDZA [m]
Decrement data memory and place result in ACC, skip if zero
Description
The contents of the specified data memory are decremented by one. If the result is zero, the next instruction is skipped. The result is stored in the accumulator but the data memory remains unchanged. If the result is zero, the
following instruction, fetched during the current instruction execution, is
discarded and a dummy cycle is replaced to get the proper instruction (two
cycles). Otherwise proceed with the next instruction (one cycle).
Operation
Skip if ([m]-1)=0, ACC ¬ ([m]-1)
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
¾
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August 18, 1999
HT49C50
SET [m]
Set data memory
Description
Each bit of the specified data memory is set to one.
Operation
[m] ¬ FFH
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
¾
SET [m].i
Set bit of data memory
Description
Bit ²i² of the specified data memory is set to one.
Operation
[m].i ¬ 1
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
¾
SIZ [m]
Skip if increment data memory is zero
Description
The contents of the specified data memory are incremented by one. If the result is zero, the following instruction, fetched during the current instruction
execution, is discarded and a dummy cycle is replaced to get the proper instruction (two cycles). Otherwise proceed with the next instruction (one cycle).
Operation
Skip if ([m]+1)=0, [m] ¬ ([m]+1)
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
¾
SIZA [m]
Increment data memory and place result in ACC, skip if zero
Description
The contents of the specified data memory are incremented by one. If the result is zero, the next instruction is skipped and the result is stored in the accumulator. The data memory remains unchanged. If the result is zero, the
following instruction, fetched during the current instruction execution, is
discarded and a dummy cycle is replaced to get the proper instruction (two
cycles). Otherwise proceed with the next instruction (one cycle).
Operation
Skip if ([m]+1)=0, ACC ¬ ([m]+1)
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
¾
47
August 18, 1999
HT49C50
SNZ [m].i
Skip if bit ²i² of the data memory is not zero
Description
If bit ²i² of the specified data memory is not zero, the next instruction is
skipped. If bit ²i² of the data memory is not zero, the following instruction,
fetched during the current instruction execution, is discarded and a dummy
cycle is replaced to get the proper instruction (two cycles). Otherwise proceed
with the next instruction (one cycle).
Operation
Skip if [m].i¹0
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
¾
SUB A,[m]
Subtract data memory from the accumulator
Description
The specified data memory is subtracted from the contents of the accumulator, leaving the result in the accumulator.
Operation
ACC ¬ ACC+[m]+1
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
Ö
Ö
Ö
Ö
SUBM A,[m]
Subtract data memory from the accumulator
Description
The specified data memory is subtracted from the contents of the accumulator, leaving the result in the data memory.
Operation
[m] ¬ ACC+[m]+1
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
Ö
Ö
Ö
Ö
SUB A,x
Subtract immediate data from the accumulator
Description
The immediate data specified by the code is subtracted from the contents of
the accumulator, leaving the result in the accumulator.
Operation
ACC ¬ ACC+x+1
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
Ö
Ö
Ö
Ö
48
August 18, 1999
HT49C50
SWAP [m]
Swap nibbles within the data memory
Description
The low-order and high-order nibbles of the specified data memory (one of
the data memories) are interchanged.
Operation
[m].3~[m].0 « [m].7~[m].4
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
¾
SWAPA [m]
Swap data memory-place result in the accumulator
Description
The low-order and high-order nibbles of the specified data memory are interchanged, writing the result to the accumulator. The contents of the data
memory remain unchanged.
Operation
ACC.3~ACC.0 ¬ [m].7~[m].4
ACC.7~ACC.4 ¬ [m].3~[m].0
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
¾
SZ [m]
Skip if data memory is zero
Description
If the contents of the specified data memory are zero, the following instruction, fetched during the current instruction execution, is discarded and a
dummy cycle is replaced to get the proper instruction (two cycles). Otherwise
proceed with the next instruction (one cycle).
Operation
Skip if [m]=0
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
¾
SZA [m]
Move data memory to ACC, skip if zero
Description
The contents of the specified data memory are copied to the accumulator. If
the contents is zero, the following instruction, fetched during the current instruction execution, is discarded and a dummy cycle is replaced to get the
proper instruction (two cycles). Otherwise proceed with the next instruction
(one cycle).
Operation
Skip if [m]=0, ACC ¬ [m]
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
¾
49
August 18, 1999
HT49C50
SZ [m].i
Skip if bit ²i² of the data memory is zero
Description
If bit ²i² of the specified data memory is zero, the following instruction,
fetched during the current instruction execution, is discarded and a dummy
cycle is replaced to get the proper instruction (two cycles). Otherwise proceed
with the next instruction (one cycle).
Operation
Skip if [m].i=0
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
¾
TABRDC [m]
Move the ROM code (current page) to TBLH and data memory
Description
The low byte of ROM code (current page) addressed by the table pointer
(TBLP) is moved to the specified data memory and the high byte transferred
to TBLH directly.
Operation
[m] ¬ ROM code (low byte)
TBLH ¬ ROM code (high byte)
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
¾
TABRDL [m]
Move the ROM code (last page) to TBLH and data memory
Description
The low byte of ROM code (last page) addressed by the table pointer (TBLP)
is moved to the data memory and the high byte transferred to TBLH directly.
Operation
[m] ¬ ROM code (low byte)
TBLH ¬ ROM code (high byte)
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
¾
XOR A,[m]
Logical XOR accumulator with data memory
Description
Data in the accumulator and the indicated data memory perform a bitwise
logical Exclusive_OR operation and the result is stored in the accumulator.
Operation
ACC ¬ ACC ²XOR² [m]
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
Ö
¾
¾
50
August 18, 1999
HT49C50
XORM A,[m]
Logical XOR data memory with the accumulator
Description
Data in the indicated data memory and the accumulator perform a bitwise
logical Exclusive_OR operation. The result is stored in the data memory. The
zero flag is affected.
Operation
[m] ¬ ACC ²XOR² [m]
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
Ö
¾
¾
XOR A,x
Logical XOR immediate data to the accumulator
Description
Data in the the accumulator and the specified data perform a bitwise logical
Exclusive_OR operation. The result is stored in the accumulator. The zero
flag is affected.
Operation
ACC ¬ ACC ²XOR² x
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
Ö
¾
¾
51
August 18, 1999
HT49C50
Holtek Semiconductor Inc. (Headquarters)
No.3 Creation Rd. II, Science-based Industrial Park, Hsinchu, Taiwan, R.O.C.
Tel: 886-3-563-1999
Fax: 886-3-563-1189
Holtek Semiconductor Inc. (Taipei Office)
5F, No.576, Sec.7 Chung Hsiao E. Rd., Taipei, Taiwan, R.O.C.
Tel: 886-2-2782-9635
Fax: 886-2-2782-9636
Fax: 886-2-2782-7128 (International sales hotline)
Holtek Microelectronics Enterprises Ltd.
RM.711, Tower 2, Cheung Sha Wan Plaza, 833 Cheung Sha Wan Rd., Kowloon, Hong Kong
Tel: 852-2-745-8288
Fax: 852-2-742-8657
Copyright Ó 1999 by HOLTEK SEMICONDUCTOR INC.
The information appearing in this Data Sheet is believed to be accurate at the time of publication. However, Holtek
assumes no responsibility arising from the use of the specifications described. The applications mentioned herein are
used solely for the purpose of illustration and Holtek makes no warranty or representation that such applications
will be suitable without further modification, nor recommends the use of its products for application that may present a risk to human life due to malfunction or otherwise. Holtek reserves the right to alter its products without prior
notification. For the most up-to-date information, please visit our web site at http://www.holtek.com.tw.
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August 18, 1999