Clocks and Power Control
MPC561/MPC563 Reference Manual, Rev. 1.2
Freescale Semiconductor
8-15
Figure 8-8. Clock Source Switching Flow Chart
NOTE
buclk_enable = (STBUC | LOC) and LME lock indicates loss of lock status
bit (LOCS) for all cases and loss of clock sticky bit (LOCSS) when state 3
is active. When buclk_enable is changed, the chip asserts HRESET to
switch the system clock to BUCLK or PLL.
At PORESET negation, if the PLL is not locked, the loss-of-clock sticky bit
(LOCSS) is asserted, and the chip should operate with BUCLK.
h
re
s
e
t_
b
=
1
bu
cl
k_
en
ab
le
=
1
asse
rt
hr
ese
t_
b
buclk_enable = 1
& hreset_b = 0
L
ME
=
1
p
o
re
se
t_
b
=
0
1,BUCLK
2,BUCLK
5, osc
poreset_b = 1
LME = 1
3,BUCLK
4, osc
6,BULCK
p
o
re
se
t_
b
=
0
h
re
se
rt
_
b
=
0
h
re
s
e
t_
b
=
1
bu
cl
k_
en
ab
le
=
1
hr
ese
t_
b
=
1
bu
clk
_e
na
ble
=0
hre
se
t_
b =
1
else
hreset_b = 0
LOCS=0
LME = 0
buclk_enable = 0
& hreset_b = 0
else
buclk_enable=0
& hreset_b=0
buclk_enable = 1
& hreset_b = 0
else
Summary of Contents for MPC561
Page 84: ...MPC561 MPC563 Reference Manual Rev 1 2 lxxxiv Freescale Semiconductor...
Page 144: ...Signal Descriptions MPC561 MPC563 Reference Manual Rev 1 2 2 46 Freescale Semiconductor...
Page 206: ...Central Processing Unit MPC561 MPC563 Reference Manual Rev 1 2 3 62 Freescale Semiconductor...
Page 302: ...Reset MPC561 MPC563 Reference Manual Rev 1 2 7 14 Freescale Semiconductor...
Page 854: ...Time Processor Unit 3 MPC561 MPC563 Reference Manual Rev 1 2 19 24 Freescale Semiconductor...
Page 968: ...Development Support MPC561 MPC563 Reference Manual Rev 1 2 23 54 Freescale Semiconductor...
Page 1144: ...Internal Memory Map MPC561 MPC563 Reference Manual Rev 1 2 B 34 Freescale Semiconductor...
Page 1212: ...TPU3 ROM Functions MPC561 MPC563 Reference Manual Rev 1 2 D 60 Freescale Semiconductor...
Page 1216: ...Memory Access Timing MPC561 MPC563 Reference Manual Rev 1 2 E 4 Freescale Semiconductor...
