36
4317I–AVR–01/08
AT90PWM2/3/2B/3B
Figure 7-4.
PCK Clocking System AT90PWM2/3
0101
Ext Osc
00
1K CK
14CK
01
1K CK
14CK + 4 ms
10
16K CK
14CK + 4 ms
11
16K CK
14CK + 64 ms
0001
Ext Clk
00
6 CK
(1)
14CK
01
6 CK
(2)
14CK + 4 ms
10
6 CK
(3)
14CK + 64 ms
11
Reserved
1.
This value do not provide a proper restart ; do not use PD in this clock scheme
2.
This value do not provide a proper restart ; do not use PD in this clock scheme
3.
This value do not provide a proper restart ; do not use PD in this clock scheme
Table 7-9.
Start-up Times when the PLL is selected as system clock
CKSEL
3..0
SUT1..0
Start-up Time from Power-down
and Power-save
Additional Delay from Reset
(V
CC
= 5.0V)
8 MHz
RC OSCILLATOR
OSCCAL
XTAL1
XTAL2
OSCILLATORS
DIVIDE
BY 8
DIVIDE
BY 2
CK
PLL
64x
PLLE
Lock
Detector
PLOCK
SOURCE
PLLF
DIVIDE
BY 4
CLK
PLL