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S Y S T E M C O N T R O L M O D U L E
Clock Configuration register
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181
Register bit
assignment
Bits
Access
Mnemonic
Reset
Description
D31:29
R/W
CSC
0x000
Clock scale control
000 Full speed (149.9136/74.9568)
001 Divide by 2 (74.9568/37.4784)
010 Divide by 4 (37.4784/18.7392)
011 Divide by 8 (18.7393/9.3693)
100 Divide by 16 (9.3693/4.6848)
Determines the frequency of the system
clock rates. The full speed rate is 150MHz for the
CPU clock and 75MHz for the AHB clock. If
CCSEL = 0, then the CPU clock will be the same
frequency as the AHB clock, 74.9568 maximum.
This register can be written on the fly.
D28:26
R/W
Max CSC
0x000
Max clock scale control
000 Full speed (149.9136/74.9568)
001 Divide by 2 (74.9568/37.4784)
010 Divide by 4 (37.4784/18.7392)
011 Divide by 8 (18.7393/9.3693)
100 Divide by 16 (9.3693/4.6848)
Software can write to the CSC bits to
reduce the clock frequency of the CPU and AHB
clocks. This register determines the maximum
system CPU and AHB clock frequencies when
returning low speed operation. This register is only
valid if the hardware clock scale control bit is set in
the Power Management register. If CCSEL = 0, then
the CPU clock will be the same frequency as the
AHB clock, 74.9568 maximum.
D25
R/W
CCSel
0x0
CPU clock select
0
CPU clock is equal to AHB clock
1
CPU clock is 2 x AHB clock
D24:18
N/A
Reserved
N/A
N/A
D17
R/W
MCOut 1
0x1
Memory clock out 1
0
Clock disabled
1
Clock enabled
D16
R/W
MCOut 0
0x1
Memory clock out 0
0
Clock disabled
1
Clock enabled
D15
N/A
Reserved
N/A
N/A
D14
R/W
EXT DMA
0x1
External DMA
0
Clock disabled
1
Clock enabled
Summary of Contents for NS9215
Page 1: ...NS9215 Hardware Reference 90000847_C Release date 10 April 2008...
Page 3: ......
Page 4: ......
Page 26: ...26 Hardware Reference NS9215...
Page 44: ...P I N O U T 26 5 System clock 44 Hardware Reference NS9215 System clock drawing...
Page 52: ...P I N O U T 26 5 Power and ground 52 Hardware Reference NS9215...
Page 80: ...I O C O N T ROL M O D U L E Memory Bus Configuration register 80 Hardware Reference NS9215...
Page 136: ...WOR KI N G W I TH T H E C P U Noncachable instruction fetches 136 Hardware Reference NS9215...
Page 202: ...S Y S T E M C O N T RO L M OD U L E RTC Module Control register 202 Hardware Reference NS9215...
Page 354: ...E X T E R N A L D M A DMA Peripheral Chip Select register 354 Hardware Reference NS9215...
Page 472: ...R E A L TI M E C L O C K M O D U L E General Status register 472 Hardware Reference NS9215...
Page 512: ...TI M I NG Clock timing 512 Hardware Reference NS9215...
Page 515: ...PA CKA GING Processor Dimensions www digiembedded com 515...
Page 516: ...PA CKA GING Processor Dimensions 516 Hardware Reference NS9215...