MC68HC05L28 Datasheet, PDF (31/156 Pages) Motorola, Inc – Flexible general-purpose microcomputer

2.2.7 PA0 – PA7, PB0 – PB7
2
These 16 I/O lines comprise ports A and B. The state of any pin is software programmable, and all
the pins are configured as inputs during power-on or reset. Port B pins in output mode can sink
10mA of current to drive the LEDs.
2.2.8 PD0 – PD5
These six I/O lines comprise port D. The state of any pin is software programmable, and all the
pins are configured as inputs during power-on or reset. This port shares its pins with the 16-bit
timer and I²C subsystems. There are four read/write registers associated with the port to select
the different functions. All the port bits can be configured as input/output pins or used by other
systems within the MCU.
This 6-bit I/O port shares its pins with other subsystems on the MCU and is controlled using the
port D control (COND) and select (SELD) registers. On reset, all registers except the data register
are cleared thereby configuring all port pins as normal inputs with pull-up resistors. Writing a ‘1’ to
any bit in COND connects the subsystem function to the corresponding port D pin.
2.2.9 BP0 – BP3, FP0 – FP17
These signals comprise the LCD driver subsystem. The subsystem has a maximum of 18
frontplanes and four backplanes.
2.2.10 AD0 – AD1, VREFH/VREFL
These 4 signals comprise the A-to-D interface. The subsystem has a maximum of two A/D
channels.
MC68HC05L28 MODES OF OPERATION AND PIN DESCRIPTIONS
TPG
MOTOROLA
2-9