MC68HC08LT8 Datasheet, PDF (102/156 Pages) Freescale Semiconductor, Inc – Microcontrollers

Input/Output (I/O) Ports
When DDRCx is a logic 1, reading address $0002 reads the PTCx data latch. When 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 9-4 summarizes the operation of the port C pins.
Table 9-4. Port C Pin Functions
DDRC
Bit
PTC Bit
I/O Pin Mode
Accesses to DDRC
Read/Write
0
X⁽¹⁾
Input, Hi-Z⁽²⁾
DDRC[7:0]
1
X
Output
DDRC[7:0]
1. X = don’t care.
2. Hi-Z = high impedance.
3. Writing affects data register, but does not affect input.
Accesses to PTC
Read
Write
Pin
PTC[7:0]⁽³⁾
PTC[7:0]
PTC[7:0]
9.5 Port D
Port D is an 8-bit special function port that shares all of its port pins with the liquid crystal display (LCD)
driver module.
9.5.1 Port D Data Register (PTD)
The port D data register contains a data latch for each of the eight port D pins.
Address:
Read:
Write:
Reset:
Alternative Function:
$0003
Bit 7
6
5
4
3
2
PTD7
PTD6
PTD5
PTD4
PTD3
PTD2
Unaffected by reset
FP18
FP17
FP16
FP15
FP14
FP13
Figure 9-12. Port D Data Register (PTD)
1
PTD1
FP12
Bit 0
PTD0
FP11
PTD[7:0] — Port D Data Bits
These read/write bits are software programmable. Data direction of each port D pin is under the control
of the corresponding bit in data direction register D. Reset has no effect on port D data.
FP[18:11] — LCD Driver Frontplanes 18–11
FP[18:11] are pins used for the frontplane output of the LCD driver module. The enable bit, PDE, in
the CONFIG2 register and LCDE bit in the LCDCR register, determines whether the
PTD7/FP18–PTD0/FP11 pins are LCD frontplane driver pins or general-purpose I/O pins. See Chapter
8 Liquid Crystal Display (LCD) Driver.
MC68HC08LT8 Data Sheet, Rev. 1
102
Freescale Semiconductor