at91sam9263 ATMEL Corporation, at91sam9263 Datasheet - Page 497

• Manufacturer Part Number: at91sam9263
• Description: At91 Arm Thumb Microcontrollers
• Manufacturer: ATMEL Corporation

32.6.1
Register Name:
Access Type:
• START: Send a START Condition
0 = No effect.
1 = A frame beginning with a START bit is transmitted according to the features defined in the mode register.
This action is necessary when the TWI peripheral wants to read data from a slave. When configured in Master Mode with a
write operation, a frame is sent as soon as the user writes a character in the Transmit Holding Register (TWI_THR).
• STOP: Send a STOP Condition
0 = No effect.
1 = STOP Condition is sent just after completing the current byte transmission in master read mode.
• MSEN: TWI Master Transfer Enabled
0 = No effect.
1 = If MSDIS = 0, the master data transfer is enabled.
• MSDIS: TWI Master Transfer Disabled
0 = No effect.
1 = The master data transfer is disabled, all pending data is transmitted. The shifter and holding characters (if they contain
data) are transmitted in case of write operation. In read operation, the character being transferred must be completely
received before disabling.
• SWRST: Software Reset
0 = No effect.
1 = Equivalent to a system reset.
497
SWRST
– In single data byte master read, the START and STOP must both be set.
– In multiple data bytes master read, the STOP must be set after the last data received but one.
– In master read mode, if a NACK bit is received, the STOP is automatically performed.
– In multiple data write operation, when both THR and shift register are empty, a STOP condition is automatically
31
23
15
–
–
–
7
sent.
AT91SAM9263 Preliminary
TWI Control Register
30
22
14
TWI_CR
–
–
–
6
–
Write-only
29
21
13
–
–
–
5
–
28
20
12
–
–
–
4
–
MSDIS
27
19
11
–
–
–
3
MSEN
26
18
10
–
–
–
2
STOP
25
17
–
–
9
–
1
6249D–ATARM–20-Dec-07
START
24
16
–
–
8
–
0