Datasheet

44
7734Q–AVR–02/12
AT90PWM81/161
start-up times.
In case of ‘Recover System Clock Source’ command, CSUT field is not affected (no recovering
of SUT code).
• Bits 3:0 – CSEL3:0: Clock Source Select
CSEL bits are initialized with the values of CKSEL Fuse bits.
In case of ‘Enable/Disable Clock Source’, ‘Request for Clock Availability’ or ‘Clock Source
Switch’ command, CSEL field gets back the code of the clock source. Refer to Table 5-1 on
page 28 and subdivisions of Section 5.2 ”Clock Sources” on page 28 for clock source codes.
In case of ‘Recover System Clock Source’ command, CSEL field receives the code of the clock
source used to drive the Clock Control Unit as described in Figure 5-1 on page 27.