Floating Point Digital Signal Processor Specification Sheet
SPRS293A − OCTOBER 2005 − REVISED NOVEMBER 2005
51
POST OFFICE BOX 1443 • HOUSTON, TEXAS 77251−1443
PLL and PLL controller (continued)
PLLDIV0, PLLDIV1, PLLDIV2, and PLLDIV3 Registers
(0x01B7 C114, 0x01B7 C118, 0x01B7 C11C, and 0x01B7 C120, respectively)
31
28 27
24 23 20 19
16
Reserved
R−0
15
14
12 11
87 54 3 21 0
DxEN Reserved PLLDIVx
R/W−1 R−0 R/W−x xxxx
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Legend: R = Read only, R/W = Read/Write; -n = value after reset
†
Default values for the PLLDIV0, PLLDIV1, PLLDIV2, and PLLDIV3 bits are /1 (0 0000), /1 (0 0000), /2 (0 0001), and /2 (0 0001), respectively.
CAUTION:
D1 and D2 should never be disabled. D3 should only be disabled if ECLKIN is used.
Table 30. PLL Wrapper Divider x Registers (Prescaler Divider D0 and Post-Scaler Dividers D1,
D2, and D3)
‡
BIT # NAME DESCRIPTION
31:16 Reserved Reserved. Read-only, writes have no effect.
15 DxEN
Divider Dx Enable (where x denotes 0 through 3).
0 – Divider x Disabled. No clock output.
1 – Divider x Enabled (default).
These divider-enable bits are device-specific and must be set to 1 to enable.
14:5 Reserved Reserved. Read-only, writes have no effect.
4:0 PLLDIVx
PLL Divider Ratio [Default values for the PLLDIV0, PLLDIV1, PLLDIV2, and PLLDIV3 bits are /1, /1,
/2, and /2, respectively].
00000 = /1 10000 = /17
00001 = /2 10001 = /18
00010 = /3 10010 = /19
00011 = /4 10011 = /20
00100 = /5 10100 = /21
00101 = /6 10101 = /22
00110 = /7 10110 = /23
00111 = /8 10111 = /24
01000 = /9 11000 = /25
01001 = /10 11001 = /26
01010 = /11 11010 = /27
01011 = /12 11011 = /28
01100 = /13 11100 = /29
01101 = /14 11101 = /30
01110 = /15 11110 = /31
01111 = /16 11111 = /32
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Note that SYSCLK2 must run at half the rate of SYSCLK1. Therefore, the divider ratio of D2 must be two times slower than D1. For example,
if D1 is set to /2, then D2 must be set to /4.