46.10.60 TWI Control Register

This register can only be written if the WPCREN bit is cleared in the TWI Write Protection Mode register.

Name: FLEX_TWI_CR
Offset: 0x600
Reset: 
Property: Write-only

Bit 3130292827262524 
   FIFODISFIFOEN LOCKCLR THRCLR 
Access WWWW 
Reset  
Bit 2322212019181716 
       ACMDISACMEN 
Access WW 
Reset  
Bit 15141312111098 
 CLEARPECRQPECDISPECENSMBDISSMBENHSDISHSEN 
Access WWWWWWWW 
Reset  
Bit 76543210 
 SWRSTQUICKSVDISSVENMSDISMSENSTOPSTART 
Access WWWWWWWW 
Reset  

Bit 29 – FIFODIS FIFO Disable

ValueDescription
0

No effect.

1

Disable the Transmit and Receive FIFOs

Bit 28 – FIFOEN FIFO Enable

ValueDescription
0

No effect.

1

Enable the Transmit and Receive FIFOs

Bit 26 – LOCKCLR Lock Clear

ValueDescription
0

No effect.

1

Clear the TWI FSM lock.

Bit 24 – THRCLR Transmit Holding Register Clear

ValueDescription
0

No effect.

1

Clear the Transmit Holding register and set TXRDY, TXCOMP flags.

Bit 17 – ACMDIS Alternative Command Mode Disable

ValueDescription
0

No effect.

1

Alternative Command mode disabled.

Bit 16 – ACMEN Alternative Command Mode Enable

ValueDescription
0

No effect.

1

Alternative Command mode enabled.

Bit 15 – CLEAR Bus CLEAR Command

When TWD (SDA)=0, the Bus Clear command must be performed via the PIO. When TWCK=0, no Bus Clear command can be issued.
ValueDescription
0

No effect.

1

When Host mode is enabled and TWD (SDA)=1, sends a Bus Clear command.

Bit 14 – PECRQ PEC Request

ValueDescription
0

No effect.

1

A PEC check or transmission is requested.

Bit 13 – PECDIS Packet Error Checking Disable

ValueDescription
0

No effect.

1

SMBus PEC (CRC) generation and check disabled.

Bit 12 – PECEN Packet Error Checking Enable

ValueDescription
0

No effect.

1

SMBus PEC (CRC) generation and check enabled.

Bit 11 – SMBDIS SMBus Mode Disabled

ValueDescription
0

No effect.

1

SMBus mode disabled.

Bit 10 – SMBEN SMBus Mode Enabled

ValueDescription
0

No effect.

1

If SMBDIS = 0, SMBus mode enabled.

Bit 9 – HSDIS TWI High-Speed Mode Disabled

ValueDescription
0

No effect.

1

High-speed mode disabled.

Bit 8 – HSEN TWI High-Speed Mode Enabled

ValueDescription
0

No effect.

1

High-speed mode enabled.

Bit 7 – SWRST Software Reset

ValueDescription
0

No effect.

1

Equivalent to a system reset.

Bit 6 – QUICK SMBus Quick Command

ValueDescription
0

No effect.

1

If Host mode is enabled, an SMBus Quick Command is sent.

Bit 5 – SVDIS TWI Client Mode Disabled

ValueDescription
0

No effect.

1

Client mode is disabled. The shifter and holding characters (if it contains data) are transmitted in the case of a read operation. In a write operation, the character being transferred must be completely received before disabling.

Bit 4 – SVEN TWI Client Mode Enabled

Switching from Host to Client mode is only permitted when TXCOMP = 1.
ValueDescription
0

No effect.

1

Enables Client mode (SVDIS must be written to 0).

Bit 3 – MSDIS TWI Host Mode Disabled

ValueDescription
0

No effect.

1

Host mode is disabled, all pending data is transmitted. The shifter and holding characters (if it contains data) are transmitted in case of write operation. In read operation, the character being transferred must be completely received before disabling.

Bit 2 – MSEN TWI Host Mode Enabled

Switching from Client to Host mode is only permitted when TXCOMP = 1.
ValueDescription
0

No effect.

1

Enables Host mode (MSDIS must be written to 0).

Bit 1 – STOP Send a STOP Condition

ValueDescription
0

No effect.

1

STOP condition is sent just after completing the current byte transmission in Host Read mode.

– In single data byte host read, both START and STOP must be set.

– In multiple data bytes host read, the STOP must be set after the last data received but one.

– In Host Read mode, if a NACK bit is received, the STOP is automatically performed.

– In host data write operation, a STOP condition will be sent after the transmission of the current data is finished.

Bit 0 – START Send a START Condition

This action is necessary when the TWI peripheral needs to read data from a client. When configured in Host mode with a write operation, a frame is sent as soon as the user writes a character in the Transmit Holding register (FLEX_TWI_THR).

ValueDescription
0

No effect.

1

A frame beginning with a START bit is transmitted according to the features defined in the TWI Host Mode register (FLEX_TWI_MMR).