AT572D940HF_08 Datasheet, PDF (384/745 Pages) ATMEL Corporation – DIOPSIS 940HF ARM926EJ-S PLUS ONE GFLOPS DSP

7. If TWI has to be set in Slave mode, wait until TXCOMP flag is at 1 and then program
the Slave mode.
Note:
In the case where the arbitration is lost and TWI is addressed, TWI will not acknowledge even if it
is programmed in Slave mode as soon as ARBLST is set to 1. Then, the Master must repeat
SADR.
Figure 25-21. Programmer Sends Data While the Bus is Busy
TWCK
TWD
TWI DATA transfer
STOP sent by the master
START sent by the TWI
DATA sent by a master
Bus is busy
Transfer is kept
Bus is free
DATA sent by the TWI
A transfer is programmed
(DADR + W + START + Write THR)
Figure 25-22. Arbitration Cases
TWCK
TWD
Bus is considered as free
Transfer is initiated
TWCK
Data from a Master
Data from TWI
TWD
S 1 0 0 11
P
S 101
Arbitration is lost
TWI stops sending data
S 1 0 0 _{1 1} Data from the master P
Arbitration is lost
S 101
The master stops sending data
S 1 0 01 ₁
S 1 0 0 1 1 Data from the TWI
ARBLST
Bus is busy
Bus is free
TWI DATA transfer
Transfer is kept
A transfer is programmed
(DADR + W + START + Write THR)
Transfer is stopped
Transfer is programmed again
(DADR + W + START + Write THR)
Bus is considered as free
Transfer is initiated
The flowchart shown in Figure 25-23 on page 385 gives an example of read and write operations
in Multi-master mode.
384 AT572D940HF Preliminary
7010A–DSP–07/08