MC68HC908AS32A Datasheet, PDF (163/280 Pages) Freescale Semiconductor, Inc – Microcontrollers

Port F
When bit DDRFx is a 1, reading address $0009 reads the PTFx data latch. When bit DDRFx is a 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 13-6 summarizes the operation of the port F pins.
Table 13-6. Port F Pin Functions
DDRF PTF
Bit
Bit
I/O Pin
Mode
Accesses to DDRF
Read/Write
0
X
Input, Hi-Z
DDRF[3:0]
1
X
Output
DDRF[3:0]
X = don’t care
Hi-Z = high impedance
1. Writing affects data register, but does not affect input.
Accesses to PTF
Read
Write
Pin
PTF[3:0]⁽¹⁾
PTF[3:0]
PTF[3:0]⁽¹⁾
MC68HC908AS32A Data Sheet, Rev. 2.0
Freescale Semiconductor
163