at91sam9g20-cu ATMEL Corporation, at91sam9g20-cu Datasheet - Page 440

• Manufacturer Part Number: at91sam9g20-cu
• Description: At91 Arm Thumb Microcontrollers
• Manufacturer: ATMEL Corporation

31.9.5.7
31.9.5.8
Figure 31-30. Repeated Start + Reversal from Read to Write Mode
31.9.5.9
Figure 31-31. Repeated Start + Reversal from Write to Read Mode
Notes:
440
TWI_RHR
TWI_RHR
TWI_THR
TWI_THR
TXCOMP
TXCOMP
EOSACC
EOSACC
SVREAD
SVREAD
RXRDY
SVACC
RXRDY
SVACC
TXRDY
TXRDY
TWD
TWD
1. In this case, if TWI_THR has not been written at the end of the read command, the clock is automatically stretched before
2. TXCOMP is only set at the end of the transmission because after the repeated start, SADR is detected again.
AT91SAM9G20 Preliminary
the ACK.
Reversal after a Repeated Start
Reversal of Read to Write
Reversal of Write to Read
S
S
As soon as a START is detected
As soon as a START is detected
SADR
SADR
The master initiates the communication by a read command and finishes it by a write command.
Figure 31-30 on page 440
1. TXCOMP is only set at the end of the transmission because after the repeated start, SADR is detected again.
The master initiates the communication by a write command and finishes it by a read com-
mand.Figure 31-31 on page 440
mode.
W
R
Read TWI_RHR
A
A
DATA0
DATA0
DATA0
A
A
DATA0
DATA1
DATA1
DATA1
describes the repeated start + reversal from Read to Write mode.
NA
A
describes the repeated start + reversal from Write to Read
DATA1
Sr
Sr
SADR
SADR
Cleared after read
Cleared after read
R
W
DATA2
A
A
DATA2
DATA2
DATA2
A
A
DATA3
DATA3
DATA3
6384B–ATARM–15-Dec-08
DATA3
NA
A
P
P