Z8PE003 Datasheet, PDF (36/48 Pages) Zilog, Inc. – FEATURE-ENHANCED Z8PLUS 1K ROM ONE-TIME PROGRAMMABLE (OTP) MICROCONTROLLER

Z8PE003
Z8Plus OTP Microcontroller
ZiLOG
PORT B
Port B Description
Port B is a 6-bit (bidirectional), CMOS-compatible I/O port.
These six I/O lines can be configured under software control
to be an input or output. Each bit is configured
independently from the other bits. That is, one bit may be
set to INPUT while another bit is set to OUTPUT.
In addition to standard input/output capability, five pins of
Port B provide special functionality as indicated in Table 15.
Special functionality is invoked via the Port B special func-
tion register. Port B, bit 5, is an open-drain-only pin when
in output mode. There is no high-side driver on the output
stage, nor is there any high-side protection device, because
PB5 acts as the V_PP pin for EPROM programming mode.
The user should always place an external protection diode
on this pin. See Figure 32.
Port
Pin
PB0
PB1
PB2
PB3
PB4
Table 15. Port B Special Functions
Input Special
Function
Stop Mode Recovery
Input
None
IRQ3
Comparator
Reference Input
Comparator Signal
Input/IRQ1/IRQ4
Output Special
Function
None
T0 Output
None
None
None
Register 0D7H
D7 D6 D5
PTBSFR
D4 D3 D2
D1 D0
1 = Enable PB0 as SMR Input
0 = No Special Functionality
1 = Enable PB1 as T0 Output
0 = No Special Functionality
1 = Enable PB2 as IRQ3 Input
0 = No Special Functionality
1 = Analog Comparator on PB3 and PB4
0 = Digital Inputs on PB3 and PB4
1 = PB4 Interrupts Enabled
0 = PB4 Interrupts Disabled
Reserved (must be 0)
Figure 32. Port B Special Function Register
36
PRELIMINARY
DS007500-Z8X0399