Low-Power Crystal Oscillator

A clarification has been made to Table 9-4 Start-Up Times for the Low-Power Crystal Oscillator Clock Selection, where 14 CK in the column Additional Delay from Reset (VCC = 5.0V) has been replaced by 19 CK. Functional changes are shown in bold.

Table 9-4. Start-Up Times for the Low-Power Crystal Oscillator Clock Selection

Oscillator Source/Power Conditions Start-Up Time from Power-Down and Power-Save Additional Delay from Reset 
(VCC = 5.0V) CKSEL0 SUT[1:0]
Ceramic resonator, fast rising power 258 CK 19 CK + 4 ms(1) 0 00
Ceramic resonator, slowly rising power 258 CK 19 CK + 65 ms(1) 0 01
Ceramic resonator, BOD enabled 1K CK 19 CK(2) 0 10
Ceramic resonator, fast rising power 1K CK 19 CK + 4 ms(2) 0 11
Ceramic resonator, slowly rising power 1K CK 19 CK + 65 ms(2) 1 00
Crystal Oscillator, BOD enabled 16K CK 19 CK 1 01
Crystal Oscillator, fast rising power 16K CK 19 CK + 4 ms 1 10
Crystal Oscillator, slowly rising power 16K CK 19 CK + 65 ms 1 11
Notes:
  1. 1.These options should only be used when not operating close to the maximum device frequency and only if frequency stability at start-up is not important for the application. These options are not suitable for crystals.
  2. 2.These options are intended for use with ceramic resonators and will ensure frequency stability at start-up. They can also be used with crystals when not operating close to the maximum device frequency and if frequency stability at start-up is unimportant for the application.