W741C260 Datasheet, PDF (22/92 Pages) Winbond – 4-BIT MICROCONTROLLER

W741C260
Input/Output Ports RA, RB
Port RA consists of pins RA.0 to RA.3 and port RB consists of pins RB.0 to RB.3. At initial reset,
input/output ports RA and RB are both in input mode. When RA and RB are used as output ports,
CMOS or NMOS open drain output type can be selected by the PM0 register. Each pin of port RA or
RB can be specified as input or output mode independently by the PM1 and PM2 registers. The
MOVA R, RA or MOVA R, RB instructions operate the input functions and the MOV RA, R or MOV
RB, R operate the output functions. For more details, refer to the instruction table and Figure 9.
DATA
BUS
Input/Output Pin of the RA(RB)
PM0.0 (or PM0.1)
V_DD
Output
Buffer
Enable
MOV RA, R
(or MOV RB, R)
Instruction
PM1.n
(or PM2.n)
Enable
MOVA R, RA
(or MOVA R, RB)
instruction
I/O PIN
RA.n(RB.n)
Figure 9. Architecture of Input/Output Pins
Input Ports RC, RD
Port RC consists of pins RC.0 to RC.3, and port RD consists of pins RD.0 to RD.3. Each pin of port
RC and port RD can be connected to a pull-up resistor, which is controlled by the port mode 0 register
(PM0). When the PEF, HEF, and IEF corresponding to the RC port are set, a signal change at the
specified pins of port RC will execute the hold mode release or interrupt subroutine. Port status
register 0 (PSR0) record the signal changing status on the port RC. PSR0 can be read out and
cleared by the MOVA R, PSR0, and CLR PSR0 instructions. Refer to Figure 10 and the instruction
table for more details. The RD port is used as input port only, it has no hold mode release or interrupt
functions.
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