Atmel SAM4L Xplained Pro Starter Kit Atmel ATSAM4L-XSTK ATSAM4L-XSTK 데이터 시트
제품 코드
ATSAM4L-XSTK
717
42023E–SAM–07/2013
ATSAM4L8/L4/L2
6.
Wait until SR.TXRDY==1, then write fourth data byte to transfer to THR.
27.8.7.2
Read Followed by Read
Consider the following transfer:
START, DADR+R, DATA+A, DATA+NA, REPSTART, DADR+R, DATA+A, DATA+NA, STOP.
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=1.
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.RXRDY==1, then read third data byte received from RHR.
6.
Wait until SR.RXRDY==1, then read fourth data byte received from RHR.
If combining several transfers, without any STOP or REPEATED START between them, remem-
ber to write a one to the ACKLAST bit in CMDR to keep from ending each of the partial transfers
with a NACK.
ber to write a one to the ACKLAST bit in CMDR to keep from ending each of the partial transfers
with a NACK.
27.8.7.3
Write Followed by Read
Consider the following transfer:
START, DADR+W, DATA+A, DATA+A, REPSTART, DADR+R, DATA+A, DATA+NA, STOP.
Figure 27-12. 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.
27.8.7.4
Read Followed by Write
Consider the following transfer:
START, DADR+R, DATA+A, DATA+NA, REPSTART, DADR+W, DATA+A, DATA+A, STOP.
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