Z8E001 Datasheet, PDF (32/49 Pages) Zilog, Inc. – CMOS OTP Microcontroller

Z8E001
CMOS OTP Microcontroller
RESET CONDITIONS
After a hardware RESET, the timers are disabled. See Ta-
ble 4 for timer control, value, and auto-initialization register
status after RESET.
Zilog
I/O PORTS
The Z8E001 has 13 lines dedicated to input and output.
These lines are grouped into two ports known as Port A
and Port B. Port A is an 8-bit port, bit programmable as
either inputs or outputs. Port B can be programmed to pro-
vide standard input/output or the following special func-
tions: timer0 output, comparator input, SMR input, and
external interrupt inputs.
All ports have push-pull CMOS outputs. In addition, the
outputs of Port A on a bit-wise basis may be configured for
open-drain operation.The ports operate on a bit-wise ba-
sis. As such, the register values for/at a given bit position
only affect the bit in question.
Each port is defined by a set of four control registers. See
Figure 25, below.
Directional Control and Special Function
Registers
Each port on the Z8E001 has an associated, dedicated Di-
rectional Control Register that determines on a bit-wise
basis whether a given port bit will operate as an input or as
an output.
Each port on the Z8E001 has a Special Function Register
that in conjunction with the directional control register im-
plements, on a bit-wise basis, any special functionality
that may be defined for each particular port bit.
Input and Output Value Registers
Each port has an Output Value Register and an Input Val-
ue Register. For port bits configured as an input by means
of the Directional Control Register, the Input Value Regis-
ter for that bit position will contain the current synchronized
input value.
For port bits configured as an output by means of the Di-
rectional Control Register, the value held in the corre-
sponding bit of the Output Value Register is driven directly
onto the output pin. The opposite register bit for a given pin
(the output register bit for an input pin and the input regis-
ter bit for an output pin) will hold their previous value. They
will not be changed by hardware nor will they have any ef-
fect on the hardware.
REGISTER
Port B SPECIAL FUNCTION
Port B DIRECTION CONTROL
Port B OUTPUT VALUE
Port B INPUT VALUE
Port A SPECIAL FUNCTION
Port A DIRECTION CONTROL
ADDRESS IDENTIFIER
0D7H PTBSFR
0D6H
0D5H
0D4H
PTBDIR
PTBOUT
PTBIN
0D3H
0D2H
PTASFR
PTADIR
Port A OUTPUT VALUE
Port A INPUT VALUE
0D1H
0D0H
PTAOUT
PTAIN
Figure 25. Z8E001 I/O Ports Registers
32
PRELIMINARY
DS97Z8X1300