 2000 Infineon Technologies Corp. • Optoelectronics Division • San Jose, CA

Appnote 17

www.infineon.com/opto • 1-888-Infineon (1-888-463-4636)

OSRAM Opto Semiconductors GmbH & Co. OHG • Regensburg, Germany

www.osram-os.com • +49-941-202-7178

5

May 31, 2000-12

Figure 7. 16-digit parallel I/O system

Figure 8. Mapped interface.

Figure 9. Interface with 6800 microprocessor

0-6

7

Display

Port A

D0

Display

Display

Display

D3

D4

D7

D8

D11

D12

D15

Port B

Port C

0

1

2

3

4

5

6

7

0

1

2

3

4

5

6

7

Control

Data

8080

µP

System

8255

Vcc

GND

D0–D6

CU

CLR

CUE

BL

3

2

1

0

WR

A

B

C

D

7442

5

/

Address

Dis play

Select

Decoder

Parallel

I/0 Device

Optional

Buffers

Reset

Int

Hold

Wait

Display Display D isplay Display

8980

Z80

6502

D15

D0

OSC

Data 0-6

Data

Control

CUE

CLR

BL

WR

Address

Data

Control

Data

Address

DBE

Decoder

6820

PIA

CUE

BL

CLR

Data

Address

Clock

Driver

6800

BA

VMA

R/W

CE CE

Reset

NMI

Halt

IRQ

TSC

Display

Display

Display

Display

Data

D15

D0

W

Figure 7 illustrates a 16 character display with an 8080 system

using the 8255 programmable peripheral interface I/O device.

The following program will display a simple 16 character mes-

sage using this interface.

I/O or Memory Mapped Addressing

Some designers may wish to avoid the additional cost of a par-

allel I/O in their system. Structuring the addressing architecture

for the 3416 to look like a set of peripheral or output devices

(I/O mapped) or RAM’s and ROM’s (memory mapped) is very

easy. Figure 8 shows the simplicity of interfacing to micropro-

cessors, such as 8080, Z80 and 6502 as examples.

The interface with the 6800 microprocessor in Figure 9 illus-

trates the need for designers to check the timing requirements

of the 3416 and the µP. The typical data output hold time is only

30 ns for DBE=

∅2 timing; two inverters in the DBE line are

added to increase the data output hold time for compatibility

with the 50 nS minimum specification of the 3416.

Conclusion

Note that although other manufacturers’ products are used in

examples, this application note does not imply specific

endorsement, or recommendation or warranty of other manu-

facturer’s products by Infineon / OSRAM.

The interface schemes shown demonstrate the simplicity of

using the 3416 with microprocessors. The slight differences

encountered with various microprocessors to interface with the

3416 are similar to those encountered when using different

RAMs. The techniques used in the examples were shown for

their generality, and any display of this family are interchange-

able in these examples. The user will undoubtedly invent other

schemes to optimize his particular system to its requirements.