ST10F280_12 datasheet(93/239 Pages) STMICROELECTRONICS

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ST10F280

Parallel ports

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Parallel ports

In order to accept or generate single external control signals or parallel data, the ST10F280

provides up to 143 parallel I/O lines, organized into two 16-bit I/O port (Port 2, XPort9), eight

8-bit I/O ports (PORT0 made of P0H and P0L, PORT1 made of P1H and P1L, Port 4, Port 6,

Port 7, Port 8), one 15-bit I/O port (Port 3) and two 16-bit input port (Port 5, XPort10).

These port lines may be used for general purpose Input/Output, controlled via software, or

may be used implicitly by ST10F280’s integrated peripherals or the External Bus Controller.

All port lines are bit addressable, and all input/output lines are individually (bit-wise)

programmable as inputs or outputs via direction registers (except Port 5, XPort10). The I/O

ports are true bidirectional ports which are switched to high impedance state when

configured as inputs. The output drivers of seven I/O ports (2, 3, 4, 6, 7, 8, 9) can be

configured (pin by pin) for push/pull operation or open-drain operation via ODPx control

registers.

The output driver of the pads are programmable to adapt the edge characteristics to the

application requirement and to improve the EMI behaviour.

This is possible using the POCONx registers for Ports P0L, P0H, P1L, P1H, P2, P3, P4, P6,

P7, P8. The output driver capabilities of ALE, RD and WR control lines are programmable

with the dedicated bits of POCON20 control register.

The input threshold levels are programmable (TTL/CMOS) for five ports (2, 3, 4, 7, 8) with

the PICON register control bits. The logic level of a pin is clocked into the input latch once

per state time, regardless whether the port is configured for input or output.

A write operation to a port pin configured as an input causes the value to be written into the

port output latch, while a read operation returns the latched state of the pin itself. A read-

modify-write operation reads the value of the pin, modifies it, and writes it back to the output

latch.

Writing to a pin configured as an output (DPx.y=‘1’) causes the output latch and the pin to

have the written value, since the output buffer is enabled. Reading this pin returns the value

of the output latch. A read-modify-write operation reads the value of the output latch,

modifies it, and writes it back to the output latch, thus also modifying the level at the pin.

Note:

The new I/O ports (XPort9, XPort10) are not mapped on the SFR space but on the internal

XBUS interface. The XPort9 and XPort10 are enabled by setting XPEN bit 2 of the SYSCON

not bit-addressable.

ST10F280 Fiches technique(PDF) 93 Page - STMicroelectronics