MC68HC908GT16 Datasheet, PDF (238/412 Pages) Motorola, Inc – Microcontrollers

Input/Output (I/O) Ports
READ DDRC ($0006)
WRITE DDRC ($0006)
RESET
WRITE PTC ($0002)
DDRCx
PTCx
V_DD
PTCPUEx
45 k
PTCx
READ PTC ($0002)
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
PTCPUE
Bit
DDRC PTC
Bit
Bit
I/O Pin
Mode
Accesses
to DDRC
Read/Write
1
0
X⁽¹⁾
Input, V_DD(2)
DDRC6–DDRC0
0
0
X
Input, Hi-Z⁽⁴⁾
DDRC6–DDRC0
X
1
X
Output
DDRC6–DDRC0
1. X = Don’t care
2. I/O pin pulled up to V_DD by internal pullup device.
3. Writing affects data register, but does not affect input.
4. Hi-Z = High impedance
Accesses
to PTC
Read
Write
Pin
PTC6–PTC0⁽³⁾
Pin
PTC6–PTC0⁽³⁾
PTC6–PTC0
PTC6–PTC0
Technical Data
238
MC68HC908GT16 • MC68HC908GT8 — Rev. 2
Input/Output (I/O) Ports
MOTOROLA