PSD913F2 datasheet(11/94 Pages) STMICROELECTRONICS

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Preliminary Information

PSD9XX Family

PSD9XX

Architectural

Overview

(cont.)

5.4 I/O Ports

The PSD9XX has 27 I/O pins divided among four ports (Port A, B, C, and D). Each

I/O pin can be individually configured for different functions. Ports A, B, C and D can

be configured as standard MCU I/O ports, PLD I/O, or latched address outputs for

microcontrollers using multiplexed address/data busses.

The JTAG pins can be enabled on Port C for In-System Programming (ISP).

Port A can also be configured as a data port for a non-multiplexed bus.

5.5 Microcontroller Bus Interface

The PSD9XX easily interfaces with most 8-bit microcontrollers that have either

multiplexed or non-multiplexed address/data busses. The device is configured to respond

to the microcontroller’s control signals, which are also used as inputs to the PLDs. Section

9.3.5 contains microcontroller interface examples.

5.6 JTAG Port

In-System Programming can be performed through the JTAG pins on Port C. This serial

interface allows complete programming of the entire PSD9XX device. A blank device can

be completely programmed. The JTAG signals (TMS, TCK, TSTAT, TERR, TDI, TDO) are

enabled on Port C when selected or when a device is blank. Table 3 indicates the JTAG

signals pin assignments.

Port C Pins

JTAG Signal

PC0

TMS

PC1

TCK

PC3

TSTAT

PC4

TERR

PC5

TDI

PC6

TDO

Table 3. JTAG Signals on Port C

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