Freescale Semiconductor MC68HC908MR16, MC68HC908MR32 Port D, Port C Pin Functions, PTC60, Output

Figure 10-10shows the port C I/O logic.

	READ DDRC ($0006)
	WRITE DDRC ($0006)
BUS	DDRCx
	RESET
DATA	WRITE PTC ($0002)
INTERNAL
	PTCx
	READ PTC ($0002)

Port D

PTCx

Figure 10-10. 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 10-3summarizes the operation of the port C pins.

Table 10-3. Port C Pin Functions

DDRC Bit	PTC Bit	I/O Pin Mode	Accesses to DDRC	Accesses to PTC
			Read/Write	Read	Write
0	X(1)	Input, Hi-Z(2)	DDRC[6:0]	Pin	PTC[6:0](3)
1	X	Output	DDRC[6:0]	PTC[6:0]	PTC[6:0]

1.X = don’t care

2.Hi-Z = high impedance

3.Writing affects data register, but does not affect input.

10.5Port D

Port D is a 7-bit, input-only port that shares its pins with the pulse width modulator for motor control module (PMC).

The port D data register (PTD) contains a data latch for each of the seven port pins.

Address:	$0003
	Bit 7	6	5	4	3	2	1	Bit 0
Read:	0	PTD6	PTD5	PTD4	PTD3	PTD2	PTD1	PTD0
Write:	R	R	R	R	R	R	R	R
Reset:				Unaffected by reset

R

= Reserved

Figure 10-11. Port D Data Register (PTD)

PTD[6:0] — Port D Data Bits

These read/write bits are software programmable. Reset has no effect on port D data.

MC68HC908MR32 • MC68HC908MR16 Data Sheet, Rev. 6.1

Freescale Semiconductor 107