MC68HC05PV8 Datasheet, PDF (96/196 Pages) Freescale Semiconductor, Inc – Techinal Data - rev 1.9

Technical Data
Freescale Semiconductor, Inc.
7.4.1 Port A Keyboard Interrupt
The keyboard interrupt consists of 8 individual edge-sensitive interrupts
with 8 interrupt flags. The keyboard interrupt is generated by a logical
OR function of the 8 interrupt flags. The interrupt inputs are connected
to PA0–7. All interrupts are maskable. If the interrupt mask bit (I bit) in
the condition code register is set, all interrupts are disabled.
The interrupts are split in two groups of four lines each (PA0–3 and
PA4–7). All interrupts of one group can be simultaneously masked by
the corresponding PAIE bits in the port A configuration register. The
trigger edges of the interrupt lines are selectable for each group with the
EDGE bits in the port A configuration register.
The port A interrupt status register indicates which interrupt request is
pending.
7.4.2 Port A Pull-up Resistors
The PA0–7 input lines have internal pull-up resistors. The port A lines
form two groups with four lines each (PA0–3 and PA4–7). All pull-up´s of
one group can be switched on with the PULEN or PUHEN bits of the port
A configuration register by resetting the bit to 0. They are disabled
• when the enable bit is set to 1
• when a line is configured as output.
7.4.3 Port A Voltage Reference for A/D Converter
The lines PA0 and PA7 can be connected to the reference inputs for the
A/D converter (VREFL and VREFH). In order to connect the reference
inputs, the corresponding VRHEN or VRLEN bits of the port A
configuration register have to be set. In addition, the corresponding lines
(PA0 or PA7) must be configured as inputs.
The pull-up resistor should be disabled when a line is used as A/D input
or A/D reference channel.
Technical Data
MC68HC(8)05PV8/A — Rev. 1.9
Input/Output Ports
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