Atmel Xplained Evaluation Board AT32UC3A3-XPLD AT32UC3A3-XPLD Data Sheet
Product codes
AT32UC3A3-XPLD
486
32072H–AVR32–10/2012
AT32UC3A3
Figure 23-12. Combining a Write and Read Transfer
To generate this transfer:
1.
Write CMDR with START=1, STOP=0, DADR, NBYTES=2 and READ=0.
2.
Write NCMDR with START=1, STOP=1, DADR, NBYTES=2 and READ=1.
3.
Wait until SR.TXRDY==1, then write first data byte to transfer to THR.
4.
Wait until SR.TXRDY==1, then write second data byte to transfer to THR.
5.
Wait until SR.RXRDY==1, then read first data byte received from RHR.
6.
Wait until SR.RXRDY==1, then read second data byte received from RHR.
23.8.7.4
Read Followed by Write
Consider the following transfer:
START, DADR+R, DATA+A, DATA+NA, REPSTART, DADR+W, DATA+A, DATA+A, STOP.
Figure 23-13. Combining a Read and Write Transfer
To generate this transfer:
1.
Write CMDR with START=1, STOP=0, DADR, NBYTES=2 and READ=1.
2.
Write NCMDR with START=1, STOP=1, DADR, NBYTES=2 and READ=0.
3.
Wait until SR.RXRDY==1, then read first data byte received from RHR.
4.
Wait until SR.RXRDY==1, then read second data byte received from RHR.
5.
Wait until SR.TXRDY==1, then write first data byte to transfer to THR.
6.
Wait until SR.TXRDY==1, then write second data byte to transfer to THR.
TWD
SR.IDLE
TXRDY
S
DADR
W
A
DATA0
A
DATA1
NA
Sr
DADR
R
A
DATA2
A
DATA3
A
P
DATA0
DATA1
THR
RXRDY
1
RHR
DATA3
DATA2
TWD
SR.IDLE
TXRDY
S
SADR
R
A
DATA0
A
DATA1
Sr
DADR
W
A
DATA2
A
DATA3
NA
P
DATA2
THR
RXRDY
RHR
DATA3
DATA0
A
1
2
DATA3
Read
TWI_RHR