Datasheet

452
32133D–11/2011
UC3D
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
SDADR WA
DATA0
A
DATA1
NA Sr
DADR
R A
DATA2
A
DATA3
A P
DATA0 DATA1
THR
RXRDY
1
RHR
DATA3DATA2
TWD
SR.IDLE
TXRDY
S SADR R A
DATA0
A
DATA1
Sr
DADR
W A
DATA2
A
DATA3
NA P
DATA2
THR
RXRDY
RHR
DATA3DATA0
A
1
2
DATA3
Read
TWI_RHR