31.8.2 ETH Control B Register

Table 31-17. Register Bit Attribute Legend
Symbol Description Symbol Description Symbol Description
R Readable bit HC Cleared by Hardware (Grey cell) Unimplemented
W Writable bit HS Set by Hardware X Bit is unknown at Reset
K Write to clear S Software settable bit
Name: CTRLB
Offset: 0x0004
Reset: 0x000000C0
Property: PAC Write Protected, Enable Write-Protected

Bit 3130292827262524 
          
Access  
Reset  
Bit 2322212019181716 
          
Access  
Reset  
Bit 15141312111098 
          
Access  
Reset  
Bit 76543210 
 TSUINC[1:0]TSUMS  TSUCLKREQ   
Access R/WR/WR/WR/W 
Reset 0100 

Bits 7:6 – TSUINC[1:0] Timer Adjust Mode

An alternative way of controlling the way the timer increment register

2’b11 = timer register increments as normal

2’b10 = timer register increments by an additional nanosecond

2’b01 = timer increments by a nanosecond less.

2’b00 = uses TSUINC

Bit 5 – TSUMS Timer Adjust

ValueDescription
0 The timer register increments as normal, but the timer value is copied to the sync strobe register
1 The “nanoseconds” timer register is cleared and the “seconds” timer register is incremented with each clock cycle.

Bit 2 – TSUCLKREQ TSU GCLK Request

ValueDescription
0 no clock request.
1 GCLK_ETH_TSU clock request