MSM80C154S/83C154S/85C154HVS

4.4.2.8 I/O control register (IOCON)

Name

Address

MSB

 

 

 

 

 

 

 

 

 

 

 

 

LSB

7

 

6

 

5

 

4

3

 

2

 

1

 

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

IOCON

0F8H

 

T32

 

SERR

 

IZC

P3HZ

 

P2HZ

 

P1HZ

 

ALF

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Bit location

Flag

 

 

 

 

 

 

Function

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

IOCON.0

ALF

If CPU power down mode (PD, HPD) is activated with this bit set

 

 

to "1", the outputs from ports 0, 1, 2, and 3 are switched to floating

 

 

status.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

When this bit is "0", ports 0, 1, 2, and 3 are in output mode.

 

 

 

 

 

IOCON.1

P1HZ

Port 1 becomes a high impedance input port when this bit is "1".

 

 

 

IOCON.2

P2HZ

Port 2 becomes a high impedance input port when this bit is "1".

 

 

 

IOCON.3

P3HZ

Port 3 becomes a high impedance input port when this bit is "1".

 

 

 

IOCON.4

IZC

The 10 kohm pull-up resistance for ports 1, 2, and 3 is switched off

 

 

when this bit is "1", leaving only the 100 kohm pull-up resistance.

 

 

 

 

 

 

 

 

 

 

IOCON.5

SERR

Serial port reception error flag.

 

 

 

 

 

 

 

 

 

This flag is set to "1" if an overrun or framing error is generated

 

 

when data is received at a serial port. The flag is reset by software.

 

 

 

IOCON.6

T32

Timer/counters 0 and 1 are connected serially to form a 32-bit

 

 

timer/counter when this bit is set to "1". TF1 of TCON is set if a

 

 

carry is generated in the 32-bit timer/counter.

 

 

 

 

 

 

 

 

 

 

 

 

 

IOCON.7

The output data is "0" if the bit is read.

 

 

 

 

 

 

 

 

This bit should not be set to "1".

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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Sonic Alert msm83c154s, msm80154s, msm85c154hvs user manual MSM80C154S/83C154S/85C154HVS 2.8 I/O control register Iocon