PSD4235G2V_09 datasheet(61/124 Pages) STMICROELECTRONICS

Part #	PSD4235G2V

Description	Flash in-system programmable (ISP) peripherals for 16-bit MCUs (3.3 V supply)

PDF	124 Pages

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Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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61 / 124 page

PSD4235G2V

Complex PLD (CPLD)

61/124

Input macrocells (IMC) are particularly useful with handshaking communication applications

where two processors pass data back and forth through a common mailbox. Figure 17

shows a typical configuration where the Master MCU writes to the Port A Data Out register.

This, in turn, can be read by the Slave MCU via the activation of the “Slave-Read” output

enable product term.

The Slave can also write to the Port A input macrocells (IMC) and the Master can then read

the input macrocells (IMC) directly.

Note that the “Slave-Read” and “Slave-Wr” signals are product terms that are derived from

the Slave MCU inputs Read Strobe (RD, CNTL1), Write Strobe (WR/WRL, CNTL0), and

Slave_CS.

Figure 15.

Input macrocell

OUTPUT

MACROCELLS A

AND

MACROCELLS B

FEEDBACK

PORT

DRIVER

I/O PIN

INTERNAL DATA BUS

DIRECTION

MUX

ALE/AS

LATCH

INPUT MACROCELL

ENABLE (.OE)

D FF

INPUT MACROCELL _ RD

AI04926

PSD4235G2V Datasheet(PDF) 61 Page - STMicroelectronics