Hyundai GMS90X51C, GMS90X52C Address Latch Enable, Circuit ground potential, No connection

HYUNDAI MicroElectronics									GMS90X5XC Series
				Pin Number			Input/
	Symbol								Function
			PLCC-		PDIP-	MQFP-	Output
			44		40	44
								The Address Latch Enable /
	ALE /		33		30	27	O			Program pulse
	PROG							Output pulse for latching the low byte of the address
								during an access to external memory. In normal
								operation, ALE is emitted at a constant rate of 1/6 the
								oscillator frequency, and can be used for external
								timing or clocking. Note that one ALE pulse is skipped
								during each access to external data memory. This pin
								is also the program pulse input (PROG) during
								EPROM programming.
								If desired, ALE operation can be disabled by setting
								bit 0 of SFR location 8EH. With this bit set, the pin is
								weakly pulled high. The ALE disable feature will be
								terminated by reset. Setting the ALE-disable bit has
								no affect if the microcontroller is in external execution
								mode.
		/ VPP	35		31	29	I	External Access Enable / Program Supply Voltage
	EA
								EA must be external held low to enable the device to
								fetch code from external program memory locations
								0000H to FFFFH. If EA is held high, the device
								executes from internal program memory unless the
								program counter contains an address greater than its
								internal memory size. This pin also receives the
								12.75V programming supply voltage (VPP) during
								EPROM programming.
								Note;	however, that if any of the Lock bits are
									programmed, EA will be internally
									latched on reset.
P0.0-P0.7			36-43		32-39	30-37	I/O	Port 0
								Port 0 is an 8-bit open-drain bidirectional I/O port.
								Port 0 pins that have 1s written to them float and can
								be used as high-impedance inputs.
								Port 0 is also the multiplexed low-order address and
								data bus during accesses to external program and
								data memory. In this application it uses strong internal
								pull-ups when emitting 1s. Port 0 also outputs the
								code bytes during program verification in the
								GMS97X5X. External pull-up resistors are required
								during program verification.
	VSS		22		20	16	-	Circuit ground potential
	VCC		44		40	38	-	Supply terminal for all operating modes
	N.C.		1,12		-	6,17	-	No connection
			23,34			28,39

8 Jan. 2001 Ver 1.0