Atmel Evaluation Kit AT91SAM9X35-EK AT91SAM9X35-EK Ficha De Dados
Códigos do produto
AT91SAM9X35-EK
744
SAM9X35 [DATASHEET]
11055E–ATARM–10-Mar-2014
38.12.1 TWI Control Register
Name: TWI_CR
Address:
0xF8010000 (0), 0xF8014000 (1), 0xF8018000 (2)
Access: Write-only
Reset: 0x00000000
• 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).
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.
– 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 master data write operation, a STOP condition will be sent after the transmission of the current data is
finished.
• MSEN: TWI Master Mode Enabled
0 = No effect.
1 = If MSDIS = 0, the master mode is enabled.
Note:
Note:
Switching from Slave to Master mode is only permitted when TXCOMP = 1.
• MSDIS: TWI Master Mode Disabled
0 = No effect.
1 = The master mode is disabled, all pending data is transmitted. The shifter and holding characters (if it contains data) are trans-
mitted in case of write operation. In read operation, the character being transferred must be completely received before disabling.
mitted in case of write operation. In read operation, the character being transferred must be completely received before disabling.
• SVEN: TWI Slave Mode Enabled
0 = No effect.
1 = If SVDIS = 0, the slave mode is enabled.
Note:
Note:
Switching from Master to Slave mode is only permitted when TXCOMP = 1.
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
–
–
–
–
–
15
14
13
12
11
10
9
8
–
–
–
–
–
–
–
–
7
6
5
4
3
2
1
0
SWRST
QUICK
SVDIS
SVEN
MSDIS
MSEN
STOP
START