3.1.1 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Low-Power Crystal Oscillator Clock Selection, where 14 CK in the column Additional Delay from Reset (V_CC = 5.0V) has been replaced by 19 CK.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  (V_CC = 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

Note:

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.
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.