Hyundai GMS90X54C, GMS90X51C Pin Number, Symbol Function, XTAL1, Program Store Enable, Reset

GMS90X5XC Series								HYUNDAI MicroElectronics
			Pin Number			Input/
Symbol								Function
		PLCC-		PDIP-	MQFP-	Output
		44		40	44
XTAL1		21		19	15	I	XTAL1
							Input to the inverting oscillator amplifier and input to
							the internal clock generator circuits.To drive the
							device from an external clock source, XTAL1 should
							be driven, while XTAL2 is left unconnected. There are
							no requirements on the duty cycle of the external
							clock signal, since the input to the internal clocking
							circuitry is divided down by a divide-by-two flip-flop.
							Minimum and maximum high and low times as well as
							rise fall times specified in the AC characteristics must
							be observed.
P2.0-P2.7		24-31		21-28	18-25	I/O	Port 2
							Port 2 is an 8-bit bidirectional I/O port with internal
							pull-ups. Port 2 pins that have 1s written to them are
							pulled high by the internal pull-up resistors and can be
							used as inputs. As inputs, port 2 pins that are
							externally pulled low will source current because of
							the pulls-ups (IIL, in the DC characteristics).Port 2
							emits the high-order address byte during fetches from
							external program memory and during accesses to
							external data memory that use 16-bit addresses
							(MOVX @DPTR). In this application it uses strong
							internal pull-ups when emitting 1s. During accesses to
							external data memory that use 8-bit addresses
							(MOVX @Ri), port 2 emits the contents of the P2
							special function register.
	PSEN	32		29	26	O	The Program Store Enable
							The read strobe to external program memory when
							the device is executing code from the external
							program memory. PSEN is activated twice each
							machine cycle, except that two PSEN activations are
							skipped during each access to external data memory.
							PSEN is not activated during fetches from internal
							program memory.
RESET		10		9	4	I	RESET
							A high level on this pin for two machine cycles while
							the oscillator is running resets the device. An internal
							diffused resistor to VSS permits power-on reset using
							only an external capacitor to VCC.

Jan. 2001 Ver 1.0 7