Renesas R5S72623 User Manual

 
Section 21   IEBus

TM

 Controller 

Page 1088 of 2108 

 

R01UH0134EJ0400  Rev. 4.00 

 

 Sep 

24, 

2014 

SH7262 Group, SH7264 Group

Figure 21.1 shows an IEBus transfer signal format. 

Communications data is transferred as a series of signals referred to as a communications frame. 
The number of data, which can be transmitted in a single communications frame and the transfer 
speed, differs according to the communications mode. 

 (When IEB

φ = 12, 18, 24, 30, or 36 MHz)

P

P A

P A

P A

P A

P A

1

Field name

Header

Master

address field

Slave address

field

Approximately 7330 

μs

Approximately 2090 

μs

Approximately 1590 

μs

Approximately 1590 

× N μs

Approximately 410 

× N μs

Approximately 300 

× N μs

Control field

Data field

Message

length field

Number

of bits

Transfer

time

Mode 0

Mode 1

Mode 2

Note: The value of acknowledge bit is ignored in broadcast communications.

P: Parity bit (1 bit)
A: Acknowledge bit (1 bit)
    When A = 0: ACK
    When A = 1: NAK
N: Number of bytes

1

Start

bit

Master

address

Slave

address

Control

bits

Data

bits

Data

bits

Message

length

bits

Broad- 

cast

bit

1

1

1

4

8

1

1

8

1

1

8

1

1

1

1

12

12

 

A header is comprised of a start bit and a broadcast bit. 

The start bit is a signal to inform other units of the start of data transfer. A unit attempting to start 
data transfer outputs a low-level signal (the start bit) for a specified period and then outputs the 
broadcast bit. 

If another unit is already outputting a start bit when a unit attempts to output a start bit, the unit 
waits for completion of the start bit from the other unit without outputting its own start bit, and 
then outputs the broadcast bit synchronized with the completion timing. 

Other units enter the receive state after detecting the start bit.