Datasheet

229
AT32UC3A
24.11.3 Read-write Flowcharts
The following flowcharts shown in Figure 24-13 to Figure 24-18 on page 234 give examples for
read and write operations. A polling or interrupt method can be used to check the status bits.
The interrupt method requires that the interrupt enable register (IER) be configured first.
Figure 24-13. TWI Write Operation with Single Data Byte without Internal Address.
Set TWI clock
(CLDIV, CHDIV, CKDIV) in TWI_CWGR
(Needed only once)
Set the Control register:
- Master enable
TWI_CR = MSEN + SVDIS
Set the Master Mode register:
- Device slave address (DADR)
- Transfer direction bit
Write ==> bit MREAD = 0
Load Transmit register
TWI_THR = Data to send
Read Status register
TXRDY = 1?
Read Status register
TXCOMP = 1?
Transfer finished
Yes
Yes
BEGIN
No
No
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