PIC16LC773T-20/SS View Datasheet(PDF) - Microchip Technology

Part Name

Description

Manufacturer

PIC16LC773T-20/SS

28/40-Pin, 8-Bit CMOS Microcontrollers w/ 12-Bit A/D

Microchip Technology 

3.6 Parallel Slave Port

The Parallel Slave Port is implemented on the

40/44-pin devices only.

PORTD operates as an 8-bit wide Parallel Slave Port,

or microprocessor port when control bit PSPMODE

(TRISE<4>) is set. In slave mode it is asynchronously

readable and writable by the external world through RD

control input pin RE0/RD and WR control input pin

RE1/WR.

It can directly interface to an 8-bit microprocessor data

bus. The external microprocessor can read or write the

PORTD latch as an 8-bit latch. Setting bit PSPMODE

enables port pin RE0/RD to be the RD input, RE1/WR

to be the WR input and RE2/CS to be the CS (chip

select) input. For this functionality, the corresponding

data direction bits of the TRISE register (TRISE<2:0>)

must be configured as inputs (set). The configuration

bits, PCFG3:PCFG0 (ADCON1<3:0>) must be config-

ured to make pins RE2:RE0 as digital I/O.

A write to the PSP occurs when both the CS and WR

lines are first detected low. A read from the PSP occurs

when both the CS and RD lines are first detected low.

PIC16C77X

FIGURE 3-13: PORTD AND PORTE BLOCK

DIAGRAM (PARALLEL SLAVE

PORT)

Data bus

DQ

WR

PORT

CK

Q

D

RD

PORT

ENEN

One bit of PORTD

Set interrupt flag

PSPIF (PIR1<7>)

RDx

pin

TTL

Read

TTL

RD

Chip Select

TTL

CS

Write

TTL

WR

Note: I/O pin has protection diodes to VDD and VSS.

FIGURE 3-14: PARALLEL SLAVE PORT WRITE WAVEFORMS

Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4

CS

WR

RD

PORTD<7:0>

IBF

OBF

PSPIF

 1999-2013 Microchip Technology Inc.

Advance Information

DS30275B-page 37

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