TMP91C824
91C824-67
Port B (PB0 to PB6)
Port B0 to PB6 is a 7-bit general-purpose I/O port. Each bit can be set individually for input or output.
Resetting sets Port B to be an input port.
In addition to functioning as a general-purpose I/O port, Port B0 has clock input terminal TA0IN of 8
bits timer 0, and port B1, B2 each has facility of 8 bits timer listing TA1OUT, TA3OUT terminal. And,
port B3 to B6 has each external interruption input facility of INT0 to INT3. Edge selection of external
interruption is establishes by IIMC register in the interrupt controller.
Timer output function and external interrupt function can be enabled by writing “1” to the
corresponding bits in the Port B Function Register (PBFC). Resetting resets all bits of the registers PBCR
and PBFC to “0”, and sets all bits to be input ports.
(1) PB0 to PB2
TA0IN
PB1 (TA1OUT)
PB2 (TA3OUT)
PB read
Timer F/F OUT
PB read
In
te
rn
a
l d
a
ta
b
u
s
Selector
A
B
S
Selector
A
B
S
Selector
A
B
S
PB0 (TA0IN)
Direction Control
(on bits basis)
S
Output latch
PBCR write
PB write
Direction Control
(on bits basis)
PBCR Write
Function control
(on bits basis)
PBFC Write
S
Output latch
PB Write
Reset
TA1OUT : Timer A1
TA3OUT : Timer A3
Reset
Figure 3.5.15 Port B0 to B2