at91sam9260-cj ATMEL Corporation, at91sam9260-cj Datasheet - Page 405

• Manufacturer Part Number: at91sam9260-cj
• Description: At91 Arm Thumb Microcontrollers
• Manufacturer: ATMEL Corporation

Figure 31-24. Read Access Ordered by a MASTER
Notes:
31.9.5.2
Figure 31-25. Write Access Ordered by a Master
Notes:
405
EOSVACC
EOSVACC
SVREAD
SVREAD
SVACC
RXRDY
TXRDY
SVACC
NACK
1. When SVACC is low, the state of SVREAD becomes irrelevant.
2. TXRDY is reset when data has been transmitted from TWI_THR to the shift register and set when this data has been
1. When SVACC is low, the state of SVREAD becomes irrelevant.
2. RXRDY is set when data has been transmitted from the shift register to the TWI_RHR and reset when this data is read.
TWD
TWD
AT91SAM9260
acknowledged or non acknowledged.
Write Operation
S
S
ADR
ADR
TWI answers with a NACK
TWI answers with a NACK
SADR does not match,
SADR does not match,
The write mode is defined as a data transmission from the master.
After a START or a REPEATED START, the decoding of the address starts. If the slave address
is decoded, SVACC is set and SVREAD indicates the direction of the transfer (SVREAD is low in
this case).
Until a STOP or REPEATED START condition is detected, TWI stores the received data in the
TWI_RHR register.
If a STOP condition or a REPEATED START + an address different from SADR is detected,
SVACC is reset.
Figure 31-25 on page 405
W
R
NA
NA
DATA
DATA
NA
NA
P/S/Sr
P/S/Sr
describes the Write operation.
Write THR
SADR
SADR
TWI answers with an ACK
TWI answers with an ACK
SADR matches,
SADR matches,
W A
R
SVREAD has to be taken into account only while SVACC is active
SVREAD has to be taken into account only while SVACC is active
A
DATA
DATA
A
A
Read RHR
ACK/NACK from the Master
A
A
DATA NA S/Sr
DATA
NA
6221G–ATARM–31-Jan-08
S/Sr
Read RHR