ATTINY87_10 Datasheet, PDF (41/292 Pages) ATMEL Corporation – 8-bit AVR Microcontroller with 8K/16K Bytes In-System Programmable Flash and LIN Controller

ATtiny87/ATtiny167
• Bits 5, 4 – CSUT1, CSUT0: Clock Start-up Time
CSUT bits are initialized with the values of SUT Fuse bits.
In case of ‘Enable/Disable Clock Source’ command, CSUT field provides the code of the clock
start-up time. Refer to subdivisions of Section 4.2 “Clock Sources” on page 25 for code of
clock start-up times.
In case of ‘Recover System Clock Source’ command, CSUT field is not affected (no recover-
ing 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 provides the code of the clock source. Refer to Table 4-1 on
page 25 and subdivisions of Section 4.2 “Clock Sources” on page 25 for clock source codes.
In case of ‘Recover System Clock Source’ command, CSEL field contains the code of the
clock source used to drive the Clock Control Unit as described in Figure 4-1 on page 24.
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