HMS87C1808B Datasheet, PDF (41/99 Pages) List of Unclassifed Manufacturers – 8-BIT SINGLE-CHIP MICROCONTROLLERS

HMS87C1X04B/08B/16B
9.2 RB and RBIO registers
RB is an 8-bit bidirectional I/O port (address C2_H). Each pin can
be set individually as input and output through the RBIO register
(address C3_H). In addition, Port RB is multiplexed with various
special features. The control register RBFUNC (address CB_H)
controls to select alternate function. After reset, this value is “0”,
port may be used as general I/O ports. To select alternate function
such as External interrupt or Timer compare output, write “1” to
the corresponding bit of RBFUNC.
RB Data Register
RB
ADDRESS : C2H
RESET VALUE : Undefined
RB7 RB6 RB5 RB4 RB3 RB2 RB1 RB0
INPUT / OUTPUT DATA
Pull-up Selection Register
PUPSEL
-
-
-
-
ADDRESS : CCH
RESET VALUE : ----_0000
PUP3 PUP2 PUP1 PUP0
RB3 / INT1 Pull-up
0 : No Pull-up
1 : With Pull-up
RB2 / INT0 Pull-up
0 : No Pull-up
1 : With Pull-up
RB Direction Register
RBIO
ADDRESS : C3H
RESET VALUE : 0000_0000
DIRECTION SELECT
0 : INPUT PORT
1 : OUTPUT PORT
Interrupt Edge Selection Register
IEDS
ADDRESS : E6H
RESET VALUE : 0000_0000
IED3H IED3L IED2H IED2L IED1H IED1L IED0H IED0L
INT3
INT2
INT1
INT0
External Interrupt Edge Select
00 : Normal I/O port
01 : Falling (1-to-0 transition)
10 : Rising (0-to-1 transition)
11 : Both (Rising & Falling)
RB Function Selection Register
RBFUNC
ADDRESS : CBH
RESET VALUE : 0000_0000
TMR2OV EC1I PWM1O PWM0O INT1I INT0I BUZO AVREFS
0 : RB7
1 : TMR2OV
0 : RB6
1 : EC1
0 : RB5
1 : PWM1 Output or
Compare Output
0 : RB4
1 : PWM0 Output or
Compare Output
0 : RB0 when ANSEL0 = 0
AN0 when ANSEL0 = 1
1 : AVref
0 : RB1
1 : BUZ Output
0 : RB2
1 : INT0
0 : RB3
1 : INT1
Figure 9-3 Registers of Port RB
Regardless of the direction register RBIO, RBFUNC is selected
to use as alternate functions, port pin can be used as a correspond-
ing alternate features.
SEP. 2004 Ver 1.03
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