W741L250 Datasheet, PDF (19/86 Pages) Winbond – 4-BIT MICROCONTROLLER

W741L250
Port Mode 2 Register (PM2)
The port mode 2 register is organized as a 4-bit binary register (PM2.0 to PM2.3). PM2 can be used
to control the input/output mode of port RB. PM2 is controlled by the MOV PM2, #I instruction. The bit
descriptions are as follows:
3210
PM2 w w w w
Note: W means write only.
Bit 0 = 0 RB.0 works as output pin. Bit 0 = 1 RB.0 works as input pin.
Bit 1 = 0 RB.1 works as output pin. Bit 1 = 1 RB.1 works as input pin.
Bit 2 = 0 RB.2 works as output pin. Bit 2 = 1 RB.2 works as input pin.
Bit 3 = 0 RB.3 works as output pin. Bit 3 = 1 RB.3 works as input pin.
After initial reset, port RB is in input mode (PM2 = 1111B).
Reset Function
The W741L250 is reset either by a power-on reset or by using the external RES pin. The initial state
of the W741L250 after the reset function is executed is described below.
Program Counter (PC)
TM0, TM1
MR0, MR1, PM0, PAGE, PMF registers
PM1, PM2 registers
PSR0 register
IEF, HEF, HCF, PEF, EVF, SEF flags
Timer 0 input clock
Timer 1 input clock
MFP output
Input/output ports RA, RB
Output port RE
RA & RB ports output type
RC & RD ports pull-high resistors
Input clock of the watchdog timer
LCD display
Segment output mode
000H
Reset
Reset
Set (1111B)
Reset
Reset
FOSC/4
FOSC
Low
Input mode
High
CMOS type
Disabled
FOSC/1024
OFF
LCD drive output
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Publication Release Date: March 1998
Revision A2