GMS81C1404 Datasheet, PDF (41/93 Pages) Hynix Semiconductor – 8-BIT SINGLE-CHIP MICROCONTROLLERS

GMS81C1404/GMS81C1408
10.4 RD and RDIO registers
RD is a 3-bit bidirectional I/O port (address C6_H). Each
pin can be set individually as input and output through the
RD Data Register
RD
ADDRESS : C6H
RESET VALUE : Undefined
RD2 RD1 RD0
INPUT / OUTPUT DATA
RD Direction Register
RDIO
ADDRESS : C7H
RESET VALUE : -----000
DIRECTION SELECT
0 : INPUT PORT
1 : OUTPUT PORT
RD Function Selection Register
RDFUNC
RDIO register (address C7_H).
Pull-up Selection Register
PUPSEL
-
-
-
-
ADDRESS : CCH
RESET VALUE : ----0000
PUP3 PUP2 PUP1 PUP0
RD1 / INT3 Pull-up
0 : No Pull-up
1 : With Pull-up
RD0 / INT2 Pull-up
0 : No Pull-up
1 : With Pull-up
Interrupt Edge Selection Register
IEDS
ADDRESS : E6H
RESET VALUE : 00000000
IED3H IED3L IED2H IED2L IED1H IED1L IED0H IED0L
INT3
INT2
INT1
INT0
ADDRESS : CDH
RESET VALUE : 00000000
External Interrupt Edge Select
00 : Normal I/O port
01 : Falling (1-to-0 transition)
10 : Rising (0-to-1 transition)
1 1: Both (Rising & Falling)
INT3I INT2I
0 : RD0
1 : INT2
0 : RD1
1 : INT3
Figure 10-5 Registers of Port RD
In addition, Port RD is multiplexed with external interrupt
input function. The control register RDFUNC (address
CD_H) controls to select alternate function. After reset, this
value is “0”, port may be used as general I/O ports. To se-
lect alternate function, write “1” to the corresponding bit of
RDFUNC.
Regardless of the direction register RDIO, RDFUNC is se-
lected to use as external interrupt input function, port pin
can be used as a interrupt input feature.
June. 2001 Ver 1.2
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