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| MC68HC908RK2 Datasheet, PDF (177/232 Pages) Motorola, Inc – Microcontroller Unit | |||
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READ DDRA ($0004)
WRITE DDRA ($0004)
RESET
WRITE PTA ($0000)
DDRAx
PTAx
Input/Output (I/O) Ports
Port A
VDD
KBIEX
INTERNAL
PULLUP
DEVICE
PTAx
READ PTA ($0000)
Figure 13-4. Port A I/O Circuit
Table 13-1. Port A Pin Functions
KBIE(2)
Bit
DDRA Bit PTA Bit I/O Pin Mode
Accesses
to DDRA
Read/Write
Accesses to PTA
Read
Write
1
X
X(1)
Input, VDD(4)
DDRA[7:0]
Pin
PTA[7:0](3)
0
0
X
Input, Hi-Z(5)
DDRA[7:0]
Pin
PTA[7:0](3)
0
1
X
Output
DDRA[7:0] PTA[7:0] PTA[7:0]
Notes:
1. X = Donât care
2. Keyboard interrupt enable bit (see 14.6.2 Keyboard Interrupt Enable Register)
3. Writing affects data register, but does not affect input.
4. I/O pin pulled up to VDD by internal pullup device
5. Hi-Z = High impedance
NOTE:
Setting a keyboard interrupt enable bit (KBIEx) forces the corresponding
keyboard interrupt pin to be an input, overriding the data direction
register. However, the data direction register bit must be a logic 0 for
software to read the pin.
MC68HC908RK2 â Rev. 4.0
MOTOROLA
Input/Output (I/O) Ports
Advance Information
177
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