PSD934F210MIT View Datasheet(PDF) - STMicroelectronics

Part Name

Description

MFG CO.

PSD934F210MIT

Flash PSD, 3.3V Supply, for 8-bit MCUs 2 Mbit + 256 Kbit Dual Flash Memories and 64 Kbit SRAM

STMicroelectronics 

PSD834F2V

Table 26. Port Data Registers

Register Name

Port

MCU Access

Data In

A,B,C,D

Read – input on pin

Data Out

A,B,C,D

Write/Read

Output Macrocell

A,B,C

Read – outputs of macrocells

Write – loading macrocells flip-flop

Mask Macrocell

A,B,C

Write/Read – prevents loading into a given

macrocell

Input Macrocell

A,B,C

Read – outputs of the Input Macrocells

Enable Out

A,B,C

Read – the output enable control of the port driver

Data In. Port pins are connected directly to the

Data In buffer. In MCU I/O input mode, the pin in-

put is read through the Data In buffer.

Data Out Register. Stores output data written by

the MCU in the MCU I/O output mode. The con-

tents of the Register are driven out to the pins if the

Direction Register or the output enable product

term is set to 1. The contents of the register can

also be read back by the MCU.

Output Macrocells (OMC). The CPLD Output

Macrocells (OMC) occupy a location in the MCU’s

address space. The MCU can read the output of

the Output Macrocells (OMC). If the OMC Mask

Register bits are not set, writing to the macrocell

loads data to the macrocell flip-flops. See the sec-

tion entitled “PLDs”, on page 27.

OMC Mask Register. Each OMC Mask Register

bit corresponds to an Output Macrocell (OMC) flip-

flop. When the OMC Mask Register bit is set to a

1, loading data into the Output Macrocell (OMC)

flip-flop is blocked. The default value is 0 or un-

blocked.

Input Macrocells (IMC). The Input Macrocells

(IMC) can be used to latch or store external inputs.

The outputs of the Input Macrocells (IMC) are rout-

ed to the PLD input bus, and can be read by the

MCU. See the section entitled “PLDs”, on page 27.

Enable Out. The Enable Out register can be read

by the MCU. It contains the output enable values

for a given port. A 1 indicates the driver is in output

mode. A 0 indicates the driver is in tri-state and the

pin is in input mode.

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