W741L250 Datasheet, PDF (18/86 Pages) Winbond – 4-BIT MICROCONTROLLER

W741L250
Port Mode 0 Register (PM0)
The port mode 0 register is organized as a 4-bit binary register (PM0.0 to PM0.3). PM0 can be used
to determine the structure of the input/output ports; it is controlled by the MOV PM0, #I instruction.
The bit descriptions are as follows:
3210
PM0 w w w w
Note: W means write only.
Bit 0 = 0 RA port is CMOS output type.
Bit 0 = 1 RA port is NMOS open drain output type.
Bit 1 = 0 RB port is CMOS output type.
Bit 1 = 1 RB port is NMOS open drain output type.
Bit 2 = 0 RC port pull-high resistor is disabled.
Bit 2 = 1 RC port pull-high resistor is enabled.
Bit 3 = 0 RD port pull-high resistor is disabled.
Bit 3 = 1 RD port pull-high resistor is enabled.
Port Mode 1 Register (PM1)
The port mode 1 register is organized as a 4-bit binary register (PM1.0 to PM1.3). PM1 can be used
to control the input/output mode of port RA. PM1 is controlled by the MOV PM1, #I instruction. The bit
descriptions are as follows:
3210
PM1 w w w w
Note: W means write only.
Bit 0 = 0 RA.0 works as output pin.
Bit 1 = 0 RA.1 works as output pin.
Bit 2 = 0 RA.2 works as output pin.
Bit 3 = 0 RA.3 works as output pin.
Bit 0 = 1 RA.0 works as input pin.
Bit 1 = 1 RA.1 works as input pin.
Bit 2 = 1 RA.2 works as input pin.
Bit 3 = 1 RA.3 works as input pin.
After initial reset, port RA is in input mode (PM1 = 1111B).
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