MC908AB32CFUE Datasheet, PDF (331/392 Pages) Freescale Semiconductor, Inc – Microcontrollers

Input/Output (I/O) Ports
NOTE:
Avoid glitches on port F pins by writing to the port F data register before
changing data direction register F bits from 0 to 1. Figure 17-20 shows
the port F I/O logic.
READ DDRF ($000D)
WRITE DDRF ($000D)
RESET
WRITE PTF ($0009)
DDRFx
PTFx
V_DD
PTFPUEx
PTFx
READ PTF ($0009)
PTF5 to TBCH1, PTF4 to TBCH0, PTF3 to TBCH3, PTF2 to TBCH2 of TIMB
PTF1 to TACH3, PTF0 to TACH2 of TIMA
Figure 17-20. Port F I/O Circuit
When DDRFx is a logic 1, reading address $0009 reads the PTFx data
latch. When 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 17-7 summarizes the operation of the port F pins.
Table 17-7. Port F Pin Functions
DDRF
Bit
0
PTF Bit
X⁽¹⁾
I/O Pin
Mode
Input, Hi-Z⁽²⁾
Accesses
to DDRF
Read/Write
DDRF[7:0]
1
X
Output
DDRF[7:0]
Notes:
1. X = don’t care.
2. Hi-Z = high impedance.
3. Writing affects data register, but does not affect the input.
Accesses to PTF
Read
Pin
PTF[7:0]
Write
PTF[7:0]⁽³⁾
PTF[7:0]
MC68HC908AB32 — Rev. 1.1
Freescale Semiconductor
Input/Output (I/O) Ports
Technical Data
331