Datasheet

Table Of Contents
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SAM9N12/SAM9CN11/SAM9CN12 [DATASHEET]
11063K–ATARM–05-Nov-13
39.8.9 Read-write Flowcharts
The following flowcharts shown in Figure 39-17 on page 718, Figure 39-18 on page 719, Figure 39-19 on page 720,
Figure 39-20 on page 721 and Figure 39-21 on page 722 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
(TWI_IER) be configured first.
Figure 39-16. 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
Ye s
Ye s
BEGIN
No
No
Write STOP Command
TWI_CR = STOP