MC68HC908AT32 Datasheet, PDF (247/378 Pages) Freescale Semiconductor, Inc – Microcontrollers

READ DDRF ($000D)
WRITE DDRF ($000D)
RESET
WRITE PTF ($0009)
DDRFx
PTFx
Port G
PTFx
READ PTF ($0009)
Figure 22-19. Port F I/O Circuit
When bit DDRFx is a logic 1, reading address $0009 reads the PTFx data latch. When bit DDRFx is a
logic 0, reading address $0009 reads the voltage level on the pin. The data latch can always be written,
regardless of the state of its data direction bit. Table 22-6 summarizes the operation of the port F pins.
Table 22-6. Port F Pin Functions
Accesses to
DDRF
PTF
I/O Pin
DDRF
Bit
Bit
Mode
Read/Write
0
X
Input, Hi-Z DDRF[6:0]
1
X
Output
DDRF[6:0]
X = don’t care
Hi-Z = high impedance
1. Writing affects data register, but does not affect input.
Accesses to PTF
Read
Pin
PTF[6:0]
Write
PTF[6:0]⁽¹⁾
PTF[6:0]
22.8 Port G
Port G is a 3-bit special function port that shares all of its pins with the keyboard interrupt module (KBD).
22.8.1 Port G Data Register
The port G data register contains a data latch for each of the three port G pins.
Address: $000A
Bit 7
6
5
4
3
2
Read: 0
0
0
0
0
PTG2
Write: R
R
R
R
R
Reset:
Unaffected by reset
Alternate Functions:
KBD2
R
= Reserved
Figure 22-20. Port G Data Register (PTG)
1
PTG1
KBD1
Bit 0
PTG0
KBD0
MC68HC908AT32 Data Sheet, Rev. 3.1
Freescale Semiconductor
247