GMS81C50 Datasheet, PDF (13/99 Pages) Hynix Semiconductor – 8-BIT SINGLE CHIP MICROCONTROLLERS

GMS81C50 Series
HYUNDAI
5. PIN FUNCTION
V_DD: Supply voltage.
V_SS: Circuit ground.
TEST: Used for shipping inspection of the IC. For normal
operation, it should be connected to V_DD.
RESET: Reset the MCU.
X_IN: Input to the inverting oscillator amplifier and input to
the internal main clock operating circuit.
X_OUT: Output from the inverting oscillator amplifier.
R00~R07: R0 is an 8-bit CMOS bidirectional I/O port. R0
pins 1 or 0 written to the Port Direction Register can be
used as outputs or inputs.
R10~R17: R1 is an 8-bit CMOS bidirectional I/O port. R1
pins 1 or 0 written to the Port Direction Register can be
used as outputs or inputs.
In addition, R1 serves the functions of the various follow-
ing special features.
Port pin
Alternate function
R11 INT1 (External Interrupt input 1)
R12 INT2 (External Interrupt input 2)
R14 /EC (Event Counter input )
R15 T2 (Timer / Counter input 2)
R16 T1 (Timer / Counter input 1)
R17 T0 (Timer / Counter input 0)
R20~R22, R30~R37 : R2 & R3 is a 8-bit CMOS bidirec-
tional I/O port. Each pins 1 or 0 written to the their Port Di-
rection Register can be used as outputs or inputs.
R40 : R40 is 1-bit CMOS bidirectional I/O port. This pin 1
or 0 written to the its Port Direction Register can be used
as outputs or inputs.
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