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¡ Semiconductor

MSM66585/586/587/P587/Q587

PIN DESCRIPTIONS

Symbol

Type

Description

P0_0-P0_7/

AD0-AD7

I/O

P1_0-P1_7/

A8-A15

I/O

P2_0-P2_3

P2_4-P2_5/

RT08-RT09

P2_6-P2_7

I/O

P4_0/ETMCK

P4_1-P4_7

I/O

P5_4/PSEN

P5_5/ALE

I/O

Port 0 is 8 input/output pins. Input or output can be specified for each bit with the

Port 0 Mode Register (P0IO). Pull-up resistors can be specified for each bit with the

Port 0 Pull-Up Register (P0PUP).

These pins also function as time-multiplexed address outputs and data input/output

pins (AD0-AD7) when accessing memory that has been expanded externally

(program or data memory).

After reset (by RES signal input, BRK instruction execution, or op code trap), P0 will

be high-impedance inputs.

Port 1 is 8 input/output pins. Input or output can be specified for each bit with the

Port 1 Mode Register (P1IO). Pull-up resistors can be specified for each bit with the

Port 1 Pull-Up Register (P1PUP).

P1_0-P1_7 also have a secondary function as input/output pins for internal operation.

Their secondary function can be set for each bit with the Port 1 Secondary Function

Control Register (P1SF). The input/output settings by P1IO will be ignored for pins

that have been set to the secondary function by P1SF.

These pins function as output pins for address A8-A15 when accessing program

memory or data memory that has been expanded externally. When the EA pin is low,

A8-A15 will be output regardless of P1SF settings.

After reset (by RES signal input, BRK instruction execution, or op code trap), P1 will

be high-impedance inputs.

P2_4 and P2_5 also have a secondary function as input/output pins for internal operation.

Their secondary function can be set for each bit with the Port 2 Secondary Function

Control Register (P2SF). The input/output settings of P2IO will be ignored for pins

that have been set to the secondary function by P2SF.

These pins output a previously set level when the value of Timer Registers 8 and 9

match a selected counter value.

After reset (by RES signal input, BRK instruction execution, or op code trap), P2 will

be high-impedance inputs.

Port 4 is 8 input/output pins. Input or output can be specified for each bit with the

Port 4 Mode Register (P4IO). Pull-up resistors can be specified for each bit with the

Port 4 Pull-Up Register (P4PUP).

P4_0 also has a secondary function as an input pin for internal operation. Its secondary

function can be set for the bit with the Port 4 Secondary Function Control Register (P4SF).

The input/output settings by P4IO will be ignored for pins that have been set to the

secondary function by P4SF.

This is the external clock input pin for the counter of a general 8-bit timer.

After reset (by RES signal input, BRK instruction execution, or op code trap), P4 will

be high-impedance inputs.

Port 5 is 2 input/output pins. Input or output can be specified for each bit with the

Port 5 Mode Register (P5IO).

P5_4 and P5_5 also have a secondary function as output pins for internal operation.

Their secondary function can be set for each bit with the Port 5 Secondary Function

Control Register (P5SF). The input/output settings of P5IO will be ignored for pins

that have been set to the secondary function by P5SF.

PSEN (P5_4):

This pin outputs the strobe signal for read operations when external program memory

is accessed. Operation will automatically switch to the secondary function when the

EA pin is low. This pin will be pulled up when both the EA pin and RESET pin are low.

ALE (P5_5):

This pin outputs the strobe for externally latching the lower 8 address bits output from

P0 when external memory is accessed. Operation will automatically switch to the

secondary function when the EA pin is low. This pin will be pulled up when both the

EA pin and RESET pin are low.

After reset (by RES signal input, BRK instruction execution, or op code trap), P5 will

be high-impedance inputs.