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Epson Research and Development

 

Vancouver Design Center

 

 

4.3 NEC VR4102Configuration

The NEC VR4102™ provides the internal address decoding necessary to map to an external LCD controller. Physical address 0A00 0000h to 0AFF FFFFh (16M bytes) is reserved for an external LCD controller.

The S1D13504 supports up to 2M bytes of display buffer. The NEC VR4102™ address line A21 is used to select between the S1D13504 display buffer and internal register set.

The VR4102™ uses a read, write and system high-byte enable to interface to an external LCD controller. The S1D13504 uses low and high byte read and write strobes and therefore minimal “glue” logic is necessary.

Table 4-2: NEC/S1D13504 Truth Table

 

 

NEC Signals

 

Cycle

S1D13504 Signals

 

 

 

 

 

SHB#

RD#

 

WR#

A0

 

 

 

 

 

 

 

 

 

 

1

0

 

1

0

8-bit even address

RD0# = low

 

Read

RD1# = high

 

 

 

 

 

 

 

 

 

 

 

 

1

0

 

1

1

8-bit odd address

RD0# = high

 

Read

RD1# - low

 

 

 

 

 

 

 

 

 

 

 

 

0

0

 

1

x

16-bit Read

RD0# = low

 

RD1# - low

 

 

 

 

 

 

 

 

 

 

 

 

 

1

1

 

0

0

8-bit even address

WR0# = low

 

Write

WR1# = high

 

 

 

 

 

 

 

 

 

 

 

 

1

1

 

0

1

8-bit odd address

WR0# = high

 

Write

WR1# = low

 

 

 

 

 

 

 

 

 

 

 

 

0

1

 

0

x

16-bit Write

WR0# = low

 

WR1# = low

 

 

 

 

 

 

 

 

 

 

 

 

 

S1D13504

Interfacing to the NEC VR4102™ Microprocessor

X19A-G-007-07

Issue Date: 01/02/02

Page 398
Image 398
Epson manual NEC VR4102 Configuration, NEC Signals Cycle S1D13504 Signals, Wr#, Write