Epson SED 1520 Series PIN DESCRIPTION, EPSON, SED1520 Series, (1) Power Pins, (2) System Bus Connection Pins

SED1520 Series

PIN DESCRIPTION

(1) Power Pins

Name	Description
VDD	Connected to the +5Vdc power. Common to the VCC MPU power pin.
VSS	0 Vdc pin connected to the system ground.
V1, V2, V3, V4, V5	Multi-level power supplies for LCD driving. The voltage determined for each liquid
	crystal cell is divided by resistance or it is converted in impedance by the op amp,
	and supplied. These voltages must satisfy the following:
	VDD ≥ V1 ≥ V2 ≥ V3 ≥ V4 ≥ V5

(2) System Bus Connection Pins

D7 to D0				Three-state I/O.
				The 8-bit bidirectional data buses to be connected to the 8- or 16-bit standard MPU
				data buses.
		A0		Input.
				Usually connected to the low-order bit of the MPU address bus and used to identify
				the data or a command.
				A0=0: D0 to D7 are display control data.
				A0=1: D0 to D7 are display data.
				Input.
	RES
				When the	RES		signal goes	the 68-series MPU is initialized, and when it
				goes		, the 80-series MPU is initialized. The system is reset during edge
				sense of the RES signal. The interface type to the 68-series or 80-series MPU is
				selected by the level input as follows:
				High level: 68-series MPU interface
				Low level: 80-series MPU interface
				Input. Active low. Effective for an external clock operation model only.
		CS
				An address bus signal is usually decoded by use of chip select signal, and it is
				entered. If the system has a built-in oscillator, this is used as an input pin to the
				oscillator amp and an Rf oscillator resistor is connected to it. In such case, the							RD,
				WR and E signals must be ORed with the					CS	signals and entered.
E				• If the 68-series MPU is connected:
			(RD)
				Input. Active high.
				Used as an enable clock input of the 68-series MPU.

•If the 80-series MPU is connected: Input. Active low.

The RD signal of the 80-series MPU is entered in this pin. When this signal is kept low, the SED1520 data bus is in the output status.

R/W (WR)	• If the 68-series MPU is connected:
	Input.
	Used as an input pin of read control signals (if R/W is high) or write control
	signals (if low).
	• If the 80-series MPU is connected:
	Input. Active low.
	The WR signal of the 80-series MPU is entered in this pin. A signal on the data
	bus is fetched at the rising edge of WR signal.

2–6 EPSON