MC68HC908JB8 Datasheet, PDF (209/286 Pages) Motorola, Inc – MICROCONTROLLERS

12.6 Port D
Input/Output Ports (I/O)
Port D
READ DDRC ($0006)
WRITE DDRC ($0006)
RESET
WRITE PTC ($0002)
READ PTC ($0002)
DDRCx
PTCx
PTCx
Figure 12-10. Port C I/O Circuit
When bit DDRCx is a logic 1, reading address $0002 reads the PTCx
data latch. When bit DDRCx is a logic 0, reading address $0002 reads
the voltage level on the pin. The data latch can always be written,
regardless of the state of its data direction bit. Table 12-4 summarizes
the operation of the port C pins.
Table 12-4. Port C Pin Functions
DDRC
Bit
0
1
PTC Bit
X⁽¹⁾
X
I/O Pin Mode
Accesses
to DDRC
Read/Write
Input, Hi-Z^{(2) DDRC[7:0]}
Output
DDRC[7:0]
Accesses to PTC
Read
Pin
PTC[7:0]
Write
PTC[7:0]⁽³⁾
PTC[7:0]
NOTES:
1. X = don’t care.
2. Hi-Z = high impedance.
3. Writing affects data register, but does not affect input.
Port D is an 8-bit general-purpose bidirectional I/O port. In 20-pin
package, PTD1 and PTD0 internal pads are bonded together to PTD0/1
pin. Port D pins are open-drain when configured as output, and can
interface with 5V logic.
MC68HC908JB8•MC68HC08JB8•MC68HC08JT8 — Rev. 2.3
Freescale Semiconductor
Input/Output Ports (I/O)
Technical Data
209