GMS81504 Datasheet, PDF (23/54 Pages) List of Unclassifed Manufacturers – CMOS SINGLE-CHIP 8-BIT MICROCONTROLLER

HYUNDAI MicroElectronics
R5 and R5DD registers: R5 is a 3-bit bidirectional
I/O port (address CAH). R55, R56 and R57 only are
physically implemented on this device.
R56, R57 have internal pullups which is activated on
input but deactivated on output. As input, these pins
that are externally pull low will source current (IP2 on
the DC characteristics) because of the internal pullups.
Caution:
Pins R56, R57 are served on 30SDIP package
only, but not served on 28SOP . Refer to Pin
assignment.
Each pin is individually configurable as input and
output through the R5DD register (address CBH).
Port Pin
R55
Alternate Function
BUZ (Square-wave output for
Buzzer driving)
The control register PMR5 (address D1H) controls the
selection alternate function. After reset, this value is
"0", port may be used as general I/O ports. To use
buzzer function, write "1" to the PMR5.
GMS81504
Port 5 Data Register
R5
- - R55 -
ADDRESS: CAH
RESET VALUE: Undefined
- - R51 R50
Input/ Output data
Port 5 Direction Register
ADDRESS: CBH
RESET VALUE: --0---00
R5DD - - R55 - - - R51 R50
Direction select
0: Input
1: Output
Port 5 Mode Register
PMR5 - - BUZS -
ADDRESS: D1H
RESET VALUE: --0-----
----
0: R55
1: BUZ (Buzzer Port)
Port 4 Mode Register
MSB
PMR4 - T1S - EC0S
ADDRESS: D0H
RESET VALUE: -0-0--00
LSB
- - INT1S INT0S
0: R46
1: T1O
0: R44
1: EC0
0: R40
1: INT0
0: R41
1: INT1
Edge Selection Register
MSB
IEDS - - - -
ADDRESS: F8H
RESET VALUE: ----0000
LSB
INT1
INT0
External Interrupt Edge select
00: Reserved
01: Falling (1-to-0 transition)
LSB
10: Rising (0-to-1 transition)
11: Both (Rising & Falling)
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