Atmel SAM9X25, Manual

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11054A–ATARM–27-Jul-11
SAM9X25
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11054A–ATARM–27-Jul-11
SAM9X25
22.13.10 PMC Clock Generator PLLA Register
Name: CKGR_PLLAR
Address: 0xFFFFFC28
Access: Read-write
Possible limitations on PLL input frequencies and multiplier factors should be checked before using the PMC.
Warning: Bit 29 must always be set to 1 when programming the CKGR_PLLAR register.
• DIVA: Divider A
• PLLACOUNT: PLLA Counter
Specifies the number of slow clock cycles before the LOCKA bit is set in PMC_SR after CKGR_PLLAR is written.
• OUTA: PLLA Clock Frequency Range
To optimize clock performance, this field must be programmed as specified in “PLL Characteristics” in the Electrical Char-
acteristics section of the product datasheet.
• MULA: PLLA Multiplier
0 = The PLLA is deactivated.
1 up to 254 = The PLLA Clock frequency is the PLLA input frequency multiplied by MULA+ 1.
31 30 29 28 27 26 25 24
– – 1 – – MULA
23 22 21 20 19 18 17 16
MULA
15 14 13 12 11 10 9 8
OUTA PLLACOUNT
7 6 5 4 3 2 1 0
DIVA
Value Divider Selected
0 Divider output is 0
1 Divider is bypassed
2 - 255 Divider output is the selected clock divided by DIVA.