MC68HC705X32CFU Freescale Semiconductor, MC68HC705X32CFU Datasheet - Page 60

• Manufacturer Part Number: MC68HC705X32CFU
• Manufacturer: Freescale Semiconductor

Specifications of MC68HC705X32CFU

• Cpu Family: HC05
• Device Core Size: 8b
• Frequency (max): 4MHz
• Interface Type: SCI
• Program Memory Type: EPROM
• Program Memory Size: 32KB
• Total Internal Ram Size: 528Byte
• # I/os (max): 32
• Number Of Timers - General Purpose: 1
• Operating Supply Voltage (typ): 5V
• Operating Supply Voltage (max): 5.5V
• Operating Supply Voltage (min): 4.5V
• On-chip Adc: 8-chx8-bit
• Instruction Set Architecture: CISC
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 64
• Package Type: PQFP
• Lead Free Status / Rohs Status: Supplier Unconfirmed

4
4.5.5
Writing a ‘1’ to any bit configures the corresponding port pin as an output; conversely, writing any
bit to ‘0’ configures the corresponding port pin as an input.
Reset clears these registers, thus configuring all ports as inputs.
4.6
All output ports can emulate ‘open-drain’ outputs. This is achieved by writing a zero to the relevant
output port latch. By toggling the corresponding data direction bit, the port pin will either be an
output zero or tri-state (an input). This is shown diagrammatically in
When using a port pin as an ‘open-drain’ output, certain precautions must be taken in the user
software. If a read-modify-write instruction is used on a port where the ‘open-drain’ is assigned and
the pin at this time is programmed as an input, it will read it as a ‘one’. The read-modify-write
instruction will then write this ‘one’ into the output data latch on the next cycle. This would cause
the ‘open-drain’ pin not to output a ‘zero’ when desired.
Note:
Port C data direction (DDRC)
Port A data direction (DDRA)
Port B data direction (DDRB)
‘Open-drain’ outputs should not be pulled above V
Data direction registers (DDRA, DDRB and DDRC)
Other port considerations
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INPUT/OUTPUT PORTS
bit 7
bit 6
bit 5
bit 4
DD
.
bit 3
Figure
bit 2
4-3.
bit 1
MC68HC05X16
bit 0
0000 0000
0000 0000
0000 0000
on reset
State
Rev. 1