Samsung S3C2440A - Manual (Page 227)

CLOCK & POWER MANAGEMENT S3C2440A RISC MICROPROCESSOR
7 -20
CLOCK GENERATOR & POWER MANAGEMENT SPECIAL REGISTER
LOCK TIME COUNT REGISTER (LOCKTIME)
Register Address R/W Description Reset Value
LOCKTIME 0x4C000000 R/W PLL lock time count register 0xFFFFFFFF
LOCKTIME Bit Description Initial State
U_LTIME [31:16] UPLL lock time count value for UCLK.
(U_LTIME 300uS)
0xFFFF
M_LTIME [15:0] MPLL lock time count value for FCLK, HCLK, and PCLK
(M_LTIME 300uS) 0xFFFF
MPLL Control Register
Mpll = (2 * m * Fin) / (p * 2 s )
m = (MDIV + 8), p = (PDIV + 2), s = SDIV
UPLL Control Register
Upll = (m * Fin) / (p * 2 s )
m = (MDIV + 8), p = (PDIV + 2), s = SDIV
PLL Value Selection Guide (MPLLCON)
1. F
out
= 2 * m * Fin / (p*2 s ), F
vco
= 2 * m * Fin / p where : m=MDIV+8, p=PDIV+2, s=SDIV
2. 600MHz ≤ F
VCO
≤ 1.2GHz
3. 200MHz ≤ FCLK
OUT
≤ 600MHz
4. Don't set the P or M value as zero, that is, setting the P=000000, M=00000000 can cause malfunction of
the PLL.
5. The proper range of P and M: 1 ≤ P ≤ 62, 1 ≤ M ≤ 248
NOTE
Although there is the rule for choosing PLL value, we recommend only the values in the PLL value recommendation
table. If you have to use another value, please contact us.