Zilog Z86193 - Manual (Page 80)

Z8
®
CPU
User Manual
UM001604-0108 Input/Output Ports
73
I
IO
For CMOS voltage comparator inputs, the input offset current (I
IO
) is the leakage current
of the CMOS input gate.
Run Mode
P33 is not available as an interrupt input during analog mode. P31 and P32 are valid inter-
rupt inputs in conjunction with P33 (Ref) when in analog mode.
P31 can still be used as T
IN
when analog mode is selected. If comparator outputs are
required to be outputted on the Port 3 outputs, refer to specific product specification for
priority of mixing when other special features are sharing those same Port 3 pins.
Halt Mode
The analog comparators are functional during HALT mode if analog mode is enabled. P31
and P32, in conjunction with P33 (Ref) are able to generate interrupts. Only P33 cannot
generate an interrupt because the P33 input goes directly to the Ref input of the compara-
tors and is disconnected from the interrupt sensing circuits.
Stop Mode
The analog comparators are disabled during STOP mode so it does not use any current at
that time. If P31, P32, or P33 are used as a source for Stop Mode Recovery, the Port 3 dig-
ital mode must be selected by setting bit D1 = 0 in the Port 3 Mode Register. Otherwise in
STOP mode, the P31, P32, and P33 cannot be sensed. If analog mode is selected when
entering STOP mode, it is still enabled after a valid SMR triggered reset.
Open-Drain Configuration
All Z8
®
MCUs can configure Port 2 to provide open-drain outputs by programming the
Port 3 Mode Register (P3M) bit D0 = 0.
Figure 61. Port 2 Configuration
D7 D6 D5 D4 D3 D2 D1 D0
(Write-Only)
0 = Pull-Ups Active
Port 2 Configuration
1 = Pull-Ups Open-Drain
Port 3 Mode Register
Register F7h