MC68HC05SU3A Datasheet, PDF (27/80 Pages) Freescale Semiconductor, Inc – Fully static chip design featuring the industry standard 8-bit M68HC05 core

Freescale Semiconductor, Inc.
3.4
Programmable Current Drive
All I/O ports (except PB0 and PB1), when programmed as outputs, can source or sink a current
of 10mA for driving LEDs directly. By setting the PIL bit in the Port Option Register (at $0A),
PB5-PB7 can be programmed to a low-current mode that source or sink only a current of 2mA
when programmed as output. This allows a direct drive to low current LEDs.
3
Note:
Although the ports each has high current drive capability, designs should limit the total
port currents to not more than 100mA.
3.5
Programmable Pull-Up Devices
Ports B, C, and D have 20KΩ pull-up resistors, which can be connected or disconnected, by
setting appropriate bits in the Port Option Register (at $0A). Port pins PB0 and PB1 each has a
permanent 1.9KΩ pull-up resistor connected.
3.5.1 Port Option Register
Port Option Register (POPR)
Address bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
State
on reset
$0A
PIL PDP PCP PBP
0000 0000
PIL — PB5:PB7 current drive select
1 (set) – PB5-PB7 are configured to 2mA drive port.
0 (clear) – PB5-PB7 are configured to 10mA drive port.
PDP — Port D Pull-up
1 (set) – The internal 20KΩ pull-up resistors are connected to the inputs of
Port D.
0 (clear) – No pull-up resistor is connected to the inputs of Port D.
PCP — Port C Pull-up
1 (set) – The internal 20KΩ pull-up resistors are connected to the inputs of
Port C.
0 (clear) – No pull-up resistor is connected to the inputs of Port C.
PBP — PB2:PB7 Pull-up
1 (set) – The internal 20KΩ pull-up resistors are connected to the inputs of
PB2-PB7.
0 (clear) – No pull-up resistor is connected to the inputs of PB2-PB7.
TPG
MC68HC05SU3A
INPUT/OUTPUT PORTS
For More Information On This Product,
3-3
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