46.10.77 TWI Filter Register

Important:

FILT and THRES are used to configure digital filters on data and clock lines.

In Standard, Fast and Fast Plus modes, the digital filter must be enabled (FILT=1) and a pulse width threshold defined (THRES > 0).

The field THRES must be set according to the peripheral clock to suppress spikes lower than 50 ns. The recommended value is calculated using the formula below:

THRES > 50 ns/tperipheral_clock (ns)

Name: FLEX_TWI_FILTR
Offset: 0x644
Reset: 0x00000000
Property: Read/Write

Bit 3130292827262524 
          
Access  
Reset  
Bit 2322212019181716 
          
Access  
Reset  
Bit 15141312111098 
      THRES[2:0] 
Access R/WR/WR/W 
Reset 000 
Bit 76543210 
       PADFENFILT 
Access R/WR/W 
Reset 00 

Bits 10:8 – THRES[2:0] Digital Filter Threshold

ValueDescription
0

No filtering applied on TWI inputs.

1–7

Maximum pulse width of spikes which will be suppressed by the input filter, defined in peripheral clock cycles.

Bit 1 – PADFEN PAD Filter Enable

ValueDescription
0

PAD analog filter is disabled.

1

PAD analog filter is enabled. (The analog filter must be enabled if High-speed mode is enabled.)

Bit 0 – FILT RX Digital Filter

TWI digital input filtering follows a majority decision based on three samples from SDA/SCL lines at peripheral clock frequency.
ValueDescription
0

No filtering applied on TWI inputs.

1

TWI input filtering is active. (Only in Standard and Fast modes)