s908ey16g2vfar Freescale Semiconductor, Inc, s908ey16g2vfar Datasheet - Page 128

• Manufacturer Part Number: s908ey16g2vfar
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Input/Output (I/O) Ports (PORTS)
When bit DDRCx is a 1, reading address $0002 reads the PTCx data latch. When bit DDRCx is a 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.
12.5 Port D
Port D is a 2-bit special function port that shares its pins with the timer interface module (TIMA).
12.5.1 Port D Data Register
The port D data register contains a data latch for each of the two port D pins.
PTD[1:0] — Port D Data Bits
12.5.2 Data Direction Register D
Data direction register D determines whether each port D pin is an input or an output. Writing a 1 to a
DDRD bit enables the output buffer for the corresponding port D pin; a 0 disables the output buffer.
128
PTD[1:0] are read/write, software programmable bits. Data direction of each port D pin is under the
control of the corresponding bit in data direction register D.
Alternative Function:
X = don’t care
Hi-Z = high impedance
1. Writing affects data register, but does not affect input.
DDRC
Bit
0
1
0
1
Address:
Reset:
Read:
Write:
PTC
Bit
X
X
2
2
$0003
MC68HC908EY16A • MC68HC908EY8A Data Sheet, Rev. 1
Bit 7
0
Figure 12-10. Port D Data Register (PTD)
Input, Hi-Z
Input, Hi-Z
I/O Pin
Output
Output
Mode
= Unimplemented
Table 12-3. Port C Pin Functions
6
0
Accesses to DDRC
5
0
Table 12-3
Read/Write
DDRC[4:0]
DDRC[4:0]
DDRC[7]
DDRC[7]
Unaffected by reset
4
0
summarizes the operation of the port C pins.
3
0
PTC[4:0]
Read
Pin
Pin
0
Accesses to PTC
2
0
TACH1
PTD1
PTC[4:0]
1
PTC[4:0]
Freescale Semiconductor
Write
PTC2
—
(1)
TACH0
PTD0
Bit 0