7480 View Datasheet(PDF) - Renesas Electronics

Part Name

Description

View to exact match

7480

SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER

Renesas Electronics 

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Application Example

Priority Control at Simplified SAEJ1850

At simplified SAEJ1850 communication, when multiple units start

to transmit data at the same time, priority control is exerted.

On the LAN data bus, the “H” level has priority over the “L” level.

When an “H” level collides with an “L” level, the LAN data bus sta-

tus goes to the “H” level.

For example, when unit A outputs “H” and unit B outputs “L” at the

same time in Figure 37, the LAN data bus goes to “H”. Accord-

ingly, unit A takes priority of control and continues its transmission,

and unit B stops its transmission immediately.

In this way, the 7480/7481 group exerts priority control for each bit

and finally allows only the highest-priority unit to transmit data.

BUS+

BUS-

MITSUBISHI MICROCOMPUTERS

7480/7481 GROUP

SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER

LAN data bus

Unit

Unit

A

B

Unit A

Unit B

LAN data bus

Fig. 37 Priority control at simplified SAEJ1850

Continue to transmit

Stop transmitting

Data collision

36

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