23.5.1 Control A

Name: CTRLA
Offset: 0x00
Reset: 0x00
Property: Enable-protected

Bit 76543210 
  CLKSEL[1:0]CNTPRES[1:0]SYNCPRES[1:0]ENABLE 
Access R/WR/WR/WR/WR/WR/WR/W 
Reset 0000000 

Bits 6:5 – CLKSEL[1:0] Clock Select

The clock select bits select the clock source of the TCD clock.

ValueDescription
0x0 OSC20M
0x1 Reserved
0x2 External clock
0x3 System clock

Bits 4:3 – CNTPRES[1:0] Counter Prescaler

The Counter Prescaler bits select the division factor of the TCD counter clock.

ValueDescription
0x0 Division factor 1
0x1 Division factor 4
0x2 Division factor 32
0x3 Reserved

Bits 2:1 – SYNCPRES[1:0] Synchronization Prescaler

The synchronization prescaler bits select the division factor of the TCD clock.

ValueDescription
0x0 Division factor 1
0x1 Division factor 2
0x2 Division factor 4
0x3 Division factor 8

Bit 0 – ENABLE Enable

When this bit is written to, it will automatically be synchronized to the TCD clock domain.

This bit can be changed as long as synchronization of this bit is not ongoing, see Enable Ready bit (ENRDY) in Status register (TCDn.STATUS).

This bit is not enable-protected.

ValueDescription
0 The TCD is disabled.
1 The TCD is enabled and running.