PLL
MCF548x Reference Manual, Rev. 3
Freescale Semiconductor 10-5

10.2 PLL

10.2.1 PLL Memory Map/Register Descriptions

10.2.2 System PLL Control Register (SPCR)

The system PLL control register (SPCR) defines the clock enables used to control clocks to a set of

peripherals. Unused peripherals can have their clock stopped, reducing power consumption. In addition,

the SPCR contains a read-only bit for the system PLL lock status. At reset, the clock enables are set,

enabling all system PLL gated output clocks.

Table 10-2. System PLL Memory Map
MBAR
Offset Name Byte0 Byte1 Byte2 Byte3 Access
0x300 System PLL Control Register SPCR R/W
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
RPLLK000000000000000
W
Reset1000000000000000
1514131211109876543210
R0
COR
EN
CRY
ENB
CRY
ENA
CAN1
EN
0PSC
EN
0USB
EN
FEC1
EN
FEC0
EN
DMA
EN
CAN0
EN
FB
EN
PCI
EN
MEM
EN
W
Reset 0111111111111111
Reg
Addr MBAR + 0x300
Figure 10-4. System PLL Control Register (SPCR)
Table 10-3. SPCR Field Descriptions
Bits Name Description
31 PLLK System PLL Lock Status - Read-only lock status of the system PLL.
1 PLL has obtained frequency lock
0 PLL has not locked
30-15 Reserved, should be cleared.
14 COREN Core & Communications Sub-System Clock Enable - Controls clocks for the CF4 Core, System
SRAM, CommBus Arbiter, I2C, Comm Timers, and External DMA modules
13 CRYENB Crypto Clock Enable B - Controls the fast clock to the SEC
12 CRYENA Crypto Clock Enable A - Controls the slow clock to the SEC
11 CAN1EN CAN1 Clock Enable
10 Reserved, should be cleared.