MC68HC705X32CFU Freescale Semiconductor, MC68HC705X32CFU Datasheet - Page 55

• 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

Freescale Semiconductor, Inc.
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INPUT/OUTPUT PORTS
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In single-chip mode, the MC68HC05X16 has a total of 24 I/O lines, arranged as three 8-bit ports
(A, B and C), and eight input-only lines, arranged as one 8-bit port (D). Each I/O line is individually
programmable as either input or output, under the software control of the data direction registers.
The 8-bit input-only port (D) shares its pins with the A/D converter, when the A/D converter is
enabled. To avoid glitches on the output pins, data should be written to the I/O port data register
before writing ones to the corresponding data direction register bits to set the pins to output mode.
4.1
Input/output programming
The bidirectional port lines may be programmed as inputs or outputs under software control. The
direction of each pin is determined by the state of the corresponding bit in the port data direction
register (DDR). Each port has an associated DDR. Any I/O port pin is configured as an output if
its corresponding DDR bit is set to a logic one. A pin is configured as an input if its corresponding
DDR bit is cleared to a logic zero.
At power-on or reset, all DDRs are cleared, thus configuring all port pins as inputs. The data
direction registers can be written to or read by the MCU. During the programmed output state, a
read of the data register actually reads the value of the output data latch and not the I/O pin. The
operation of the standard port hardware is shown schematically in
Figure
4-1.
MC68HC05X16
INPUT/OUTPUT PORTS
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4-1
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