Cirrus Logic EP93xx User Manual

Page 145

DS785UM1

5-19

System Controller

EP93xx User’s Guide

PLL1_X2FBD2:

These 6 register bits set the first feedback divider bits for
PLL1. On power-on-reset the value is set to 000111b (7
decimal).

Note: The value in the register is the actual coefficient minus one.

PLL1_X1FBD1:

These 5 register bits set the second feedback divider bits
for PLL1. On power-on-reset the value is set to 10011b (19
decimal).

Note: The value in the register is the actual coefficient minus one.

PLL1_PS:

These two bits determine the final divide on the VCO clock
signal in PLL1.
00 - Divide by 1
01 - Divide by 2
10 - Divide by 4
11 - Divide by 8

On power-on-reset these bits are reset to 11b (3 decimal).

Note: This means that PLL1 FOUT is programmed to be 36,864,000 Hz on startup.

Note: The value in the register is the actual coefficient minus one.

PCLKDIV:

These two bits set the divide ratio between the HCLK AHB
clock and the APB clock (PCLK)
00 - Divide by 1
01 - Divide by 2
10 - Divide by 4
11 - Divide by 8

On power-on-reset the value is set to 00b.

Note: Care must be taken to make the correct selection of PCLK divide for the HCLK frequency

used, so that the required minimum ratio between PCLK and the peripheral clock is not
violated

HCLKDIV:

These three bits set the divide ratio between the VCO
output and the bus clock (HCLK)
000 - Divide by 1 100 - Divide by 6
001 - Divide by 2 101 - Divide by 8
010 - Divide by 4 110 - Divide by 16
011 - Divide by 5 111 - Divide by 32

On power-on-reset the value is set to 000b.