mc68hc908mr24 Freescale Semiconductor, Inc, mc68hc908mr24 Datasheet - Page 329

• Manufacturer Part Number: mc68hc908mr24
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

MC68HC908MR24 — Rev. 4.1
Freescale Semiconductor
NOTE:
DDRC[6:0] — Data Direction Register C Bits
Avoid glitches on port C pins by writing to the port C data register before
changing data direction register C bits from 0 to 1.
Figure 15-10
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.
the operation of the port C pins.
DDRC
1. X = don’t care
2. Hi-Z = high impedance
3. Writing affects data register, but does not affect input.
These read/write bits control port C data direction. Reset clears
DDRC[6:0], configuring all port C pins as inputs.
Bit
0
1
1 = Corresponding port C pin configured as output
0 = Corresponding port C pin configured as input
READ DDRC ($0006)
WRITE DDRC ($0006)
WRITE PTC ($0002)
READ PTC ($0002)
PTC Bit
X
X
(1)
shows the port C I/O logic.
Input/Output (I/O) Ports
Table 15-3. Port C Pin Functions
Figure 15-10. Port C I/O Circuit
I/O Pin Mode
RESET
Input, Hi-Z
Output
(2)
DDRCx
PTCx
Read/Write
DDRC[6:0]
DDRC[6:0]
Accesses
to DDRC
Table 15-3
PTC[6:0]
Read
Input/Output (I/O) Ports
Accesses to PTC
Pin
Advance Information
summarizes
PTC[6:0]
PTC[6:0]
Write
PTCx
(3)
329