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Section 8 I/O Ports
8.11
Port A
8.11.1
Overview
Port A is an 8-bit input/output port that is also used for output (TP
timing pattern controller (TPC), input and output, (TIOCB
TIOCA
, TCLKD, TCLKC, TCLKB, TCLKA) by the 16-bit timer, input (TCLKD, TCLKC,
0
TCLKB, TCLKA) to the 8-bit timer, output (TEND
and address output (A
port, except that in modes 3 and 4, one pin is always used for A
the selection of pin functions.
Usage of pins for TPC, 16-bit timer, 8-bit timer, and DMAC input and output is described in the
sections on those modules. For output of address bits A
6.2.4, Bus Release Control Register (BRCR). Pins not assigned to any of these functions are
available for generic input/output. Figure 8.10 shows the pin configuration of port A.
Pins in port A can drive one TTL load and a 30-pF capacitive load. They can also drive a
darlington transistor pair. Port A has Schmitt-trigger inputs.
Rev. 4.00 Jan 26, 2006 page 306 of 938
REJ09B0276-0400
to A
). A reset or hardware standby transition leaves port A as an input
23
20
to TP
7
0
, TIOCA
, TIOCB
2
2
, TEND
) from the DMA controller (DMAC),
1
0
output. See table 8.19 to 8.21 for
20
to A
in modes 3, 4, and 5, see section
23
20
) from the programmable
, TIOCA
, TIOCB
1
1
,
0
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