CHAPTER 13 GENERAL PURPOSE I/O UNIT (GIU)
User’s Manual U14272EJ3V0UM
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The second group, GPIO(31:16) pins, are capable of supporting the following types of functions:
•
External ISA I/O interface
•
External 16-bit bus sizing signal
•
ROM chip select
•
Serial interface channel 1
•
General-purpose input
•
General-purpose output
Remark GPIO(31:16) pins can not be used as interrupt/wake-up inputs.
The assignment of interface signals to particular GPIO pins is shown in the following table:
Table 13-2. Alternate Functions of GPIO(31:16) Pins
GPIO pin
Alternate signal
1
Alternate signal
2
Definition
GPIO31
DSR1#
−
SIU1 DSR input
GPIO30
DTR1#
−
SIU1 DTR output
GPIO29
DCD1#
−
SIU1 DCD input
GPIO28
CTS1#
−
SIU1 CTS input
GPIO27
RTS1#
−
SIU1 RTS output
GPIO26
TxD1
−
SIU1 transmit data output
GPIO25
RxD1
−
SIU1 receive data input
GPIO24
ROMCS2#
−
ROM chip select for bank 2
GPIO23
ROMCS1#
−
ROM chip select for bank 1
GPIO22
ROMCS0#
−
ROM chip select for bank 0
GPIO21
RESET#
−
External ISA reset
GPIO20
Note
UBE#
M
External ISA upper byte enable or LCD modulation output
GPIO19
IOCS16#
−
External ISA I/O 16-bit bus sizing
GPIO18
IORDY
−
External ISA I/O channel ready
GPIO17
IOWR#
−
External ISA I/O write strobe
GPIO16
IORD#
−
External ISA I/O read strobe
Note This signal supports input only.
The GPIO29/DCD1# pin can be used as an activation (wake-up) factor from Hibernate mode if enabled by
software. The other pins listed above are only capable of providing general-purpose input or output, or the alternate
function listed.