441
Section 16 I/O Ports (I/O)
16.1
Overview
There are three ports, A, B, and C. Ports A and B are 16-bit I/O ports, while port C is an 8-bit
input port. The pins of the ports are all multiplexed for use as general-purpose I/Os (or inputs in
the case of port C) or for other functions. (Use the pin function controller (PFC) to select the
function of multiplexed pins.) Ports A, B, and C each have one data register for storing pin data.
16.2
Port A
Port A is a 16-pin input/output port, as shown in figure 16.1. The PA3/
CS7
/
WAIT
pin of port A
has a pull-up MOS so that when it is functioning as a
WAIT
pin, the wait state control register of
the bus state controller can be used to select whether to pull up the
WAIT
pin or not. It is not
pulled up when the pin is functioning as either PA3 or
CS7
.
Port A
PA
15
(Input/output)/
IRQ3
(Input)/
DREQ1
(Input)
PA
14
(Input/output)/
IRQ2
(Input)/DACK1 (Output)
PA
13
(Input/output)/
IRQ1
(Input)/
DREQ0
(Input)/TCLKB (Input)
PA
12
(Input/output)/
IRQ0
(Input)/DACK0 (Output)/TCLKA (Input)
PA
11
(Input/output)/DPH (Input/output)/TIOCB1 (Input/output)
PA
10
(Input/output)/DPL (Input/output)/TIOCA1 (Input/output)
PA
9
(Input/output)/
AH
(Output)/
IRQOUT
(Output)/
ADTRG
(Input)
PA
8
(Input/output)/
BREQ
(Input)
PA
7
(Input/output)/
BACK
(Output)
PA
6
(Input/output)/
RD
(Output)
PA
5
(Input/output)/
WRH
(Output) (
LBS
(Output))
PA
4
(Input/output)/WRL (Output) (
WR
(Output))
PA
3
(Input/output)/
CS7
(Output)/
WAIT
(Input)
PA
2
(Input/output)/
CS6
(Output)/TIOCB0 (Input/output)
PA
1
(Input/output)/
CS5
(Output)/
RAS
(Output)
PA
0
(Input/output)/
CS4
(Output)/TIOCA0 (Input/output)
Figure 16.1 Port A Configuration
16.2.1
Register Configuration
Table 16.1 summarizes the port A register.
Summary of Contents for HD6417032
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Page 525: ...490 CK RAS CAS TRp TRc TRcc tRASD1 tRASD2 tCASD3 tCASD2 TRr tCSR Figure 20 18 Self Refresh ...
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