Renesas Hitachi H8S/2191, Hardware Manual

Page: 598 / 1065

Rev. 2.0, 11/00, page 571 of 1037
(8) Notes on Start Condition Issuance for Retransmission
Figure 25.19 shows the timing of start conditon issuance for retransmission, and the timing for
subsequently writing data to ICDR, together with the corresponding flowchart. After start
condition issuance is done and determined the start condition, write the transmit data to ICDR.
IRIC=1 ?
SCL=Low ?
IRIC=1 ?
Write transmit data to ICDR
Write BBSY=1,
SCP=0 (ICSR)
Clear IRIC in ICSR
Read SCL pin
Start condition
issuance?
Other processing
No
[1]
[2]
[3]
[4]
[5]
No
No
Yes
Yes
Yes
Yes
No
[1] Wait for end of 1-byte transfer
[2] Determine wheter SCL is low
[3] Issue restart condition instruction for transmission
[4] Determine whether start condition is generated or not
[5] Set transmit data (slave a R/ )
Note: Program so that processing instruction [3] to [5] is
executed continuously.
[5] ICDR write (next transmit data)
[4] IRIC determination
[2] Determination of SCL=Low
[1] IRIC determination
SCL
SDA ACK bit 7
9
IRIC
Start condition
(retransmission)
[3] Issue restart condition instruction
for retransmission
Figure 25.19 Flowchart and Timing of Start Condition Instruction Issuance for
Retransmission