Hardware manual

Rev. 3.0, 09/98, page 105 of 361
6.7 Port 6
Port 6 is an 8-bit input/output port that also provides the input and output pins for the free-running
timer and the IRQ
6
and
IRQ
7
input/output pins. The pin functions depend on control bits in the
free-running timer control registers, and on bit 6 or 7 of the interrupt enable register. Pins not used
for timer or interrupt functions are available for general-purpose input/output. Table 6.15 lists the
pin functions, which are the same in both the expanded and single-chip modes.
Table 6.15 Port 6 Pin Functions
Usage Pin Functions (Modes 1 to 3)
I/O port P6
0
P6
1
P6
2
P6
3
P6
4
P6
5
P6
6
P6
7
Timer/interrupt FTCI FTOA FTIA FTIB FTIC FTID FTOB/IRQ
6
IRQ
7
See section 4 “Exception Handling” and section 6, “16-Bit Free-Running Timer” for details of the
free-running timer and interrupts.
Pins of port 6 can drive a single TTL load and a 90pF capacitive load when they are used as output
pins. They can also drive a Darlington pair.
Table 6.16 details the port 6 registers.
Table 6.16 Port 6 Registers
Name Abbreviation Read/Write Initial Value Address
Port 6 data direction register P6DDR W H'00 H'FFB9
Port 6 data register P6DR R/W H'00 H'FFBB
Port 6 Data Direction Register (P6DDR)H'FFB9
Bit:76543210
P6
7
DDR P6
6
DDR P6
5
DDR P6
4
DDR P6
3
DDR P6
2
DDR P6
1
DDR P6
0
DDR
Initial value:00000000
Read/Write: W W W W W W W W
P6DDR is an 8-bit register that selects the direction of each pin in port 6. A pin functions as an
output pin if the corresponding bit in P6DDR is set to “1,” and as an input pin if the bit is cleared
to “0.”