MC908GR8CDWE Datasheet, PDF (218/408 Pages) Freescale Semiconductor, Inc – M68HC08 Microcontrollers

Freescale Semiconductor, Inc.
Input/Output Ports (I/O)
READ DDRC ($0006)
WRITE DDRC ($0006)
RESET
WRITE PTC ($0002)
V_DD
DDRCx
PTCx
PTCPUEx
READ PTC ($0002)
INTERNAL
PULLUP
DEVICE
PTCx
Figure 16-11. 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 16-4 summarizes
the operation of the port C pins.
Table 16-4. Port C Pin Functions
Accesses to DDRC
PTCPUE Bit DDRC Bit PTC Bit I/O Pin Mode
Read/Write
Accesses to PTC
Read
Write
1
0
X⁽¹⁾
Input, V_DD(4)
DDRC1–DDRC0
Pin
PTC1–PTC0⁽³⁾
0
0
X
Input, Hi-Z^{(2) DDRC1–DDRC0}
Pin
PTC1–PTC0⁽³⁾
X
1
X
Output
DDRC1–DDRC0 PTC1–PTC0 PTC1–PTC0
Notes:
1. X = Don’t care
2. Hi-Z = High impedance
3. Writing affects data register, but does not affect input.
4. I/O pin pulled up to V_DD by internal pullup device.
Technical Data
218
MC68HC908GR8 — Rev 4.0
Input/Output Ports (I/O)
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