psd511b1 STMicroelectronics, psd511b1 Datasheet - Page 48

• Manufacturer Part Number: psd511b1
• Description: Low Cost Field Programmable Microcontroller Peripherals
• Manufacturer: STMicroelectronics

I/O Ports
(Cont.)
9.3.11 Port A – Functionality and Structure
Port A is the most flexible of all the I/O ports. It can be configured to perform one or more
of the following functions:
Figure 21 shows the structure of a Port A pin. If the pin is configured as an output port, the
multiplexer selects one of its four inputs as output. If the pin is configured as an input, the
input connects to :
1. Data In Register as input in Standard MCU I/O Mode
or
2. PA Macrocell as PLD input
or
3. PA Macrocell as Address In input (latched for multiplexed bus).
9.3.12 Port B – Functionality and Structure
Port B is similar to Port A in structure. It can be configured to perform one or more of the
following functions:
Figure 22 shows the structure of a Port B pin. If the pin is configured as an output port, the
multiplexer selects one of its four inputs as output. If the pin is configured as input, the input
connects to :
or
Standard MCU I/O Mode
PLD I/O
Address Out – latched address lines assigned to pins PA[0-7]
Address In – input port for other lines, inputs can be latched by ALE.
Special Function Out – pins PA0 – PA3 can be configured as dedicated timer outputs.
Peripheral I/O
Standard MCU I/O Mode
PLD I/O
Address Out – address lines A[0-7] for 8-bit multiplexed bus, or address lines
A[8-15] for 16-bit multiplexed bus are assigned to pins PB[0-7].
Special Function Out – pins PB0 - PB3 are configured as dedicated Timer outputs.
Data In Register as input in Standard MCU I/O Mode
PB Macrocell as PLD input
PSD5XX Family
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