TMP92CM22 2007-02-16 92CM22-73
3.5.11 Port F (PF0 to PF7)
Port F is 8-bit general-purpose I/O port. Each bit can be set individually for input or
output. Resetting resets the PFCR and PFFC to “0”, and sets all bits to input port. And all
bits of output latch register to “1”.
In addition to functioning as a general-purpose I/O port, port F can also function as I/O
function of serial channel 0 and 1.
These settings operate by writing “1” to the corresponding bit of PFFC.
Resetting resets the PDCR and PDFC to “0”, and sets all bits to input port.
(1) Port PF0 and PF3 (TXD0/TXD1)
In addition to function as I/O port, port PF0 and PF3 can also function as TXD output
pin of serial channel.
Thus, output buffer feature a programmable open-drain function, and setting enable by
PFFC<PF0F, PF3F> and PFCR<PF0C, PF3C> register.
Figure 3.5.25 Port F (PF0 and PF3)
Internal data bus
Direction control
(on bit basis)
Reset
PFCR write
PF write
PF read
PF0 (TXD0)
PF3
(
TXD1
)
Function control
(on bit basis)
PFFC write
S
Output latch
SB
Selector
A
S
A
Selector
B
TXD0, TXD1 Open-drain enable
<PF0F = 1, PF0C = 0
PF3F = 1, PF3C = 0>