DS632F1
51
CS44800
7.3
Clock Configuration and Power Control (address 02h)
7.3.1
Enable SYS_CLK Output (EN_SYS_CLK)
Default = 1
Function:
This bit enables the driver for the SYS_CLK signal. If the SYS_CLK output is unused, this bit should be
set to ‘0’b to disable the driver.
7.3.2
SYS_CLK Clock Divider Settings (SYS_CLK_DIV[1:0])
Default = 00
Function:
These two bits determine the divider for the XTAL clock signal for generating the SYS_CLK signal. During
a reset condition, with the RST input pin held low, the logic level on the MUTE input pin will determine the
divider used for the SYS_CLK output. If MUTE is pulled low, the SYS_CLK divider will be set to divide
the clock frequency on XTI by a factor of 1. If the MUTE pin is pulled high, the SYS_CLK output will be
set to perform a divide-by-2 on the XTI clock. The state of the MUTE pin will be latched on the rising edge
of the RST. The MUTE pin can then be used as defined.
7.3.3
PWM Master Clock Divider Settings (PWM_MCLK_DIV[1:0])
Default = 00
Function:
These two bits determine the divider for the XTAL clock signal for generating the PWM_MCLK signal.
7.3.4
Power Down XTAL (PDN_XTAL)
Default = 0
0 - Crystal Oscillator Circuit is running.
1 - Crystal Oscillator Circuit is powered down.
Function:
This bit is used to power down the crystal oscillator circuitry when not being used. When using a clock
signal attached to the XTI input, this bit should be set to ‘1’b.
7
6
5
4
3
2
1
0
EN_SYS_CLK SYS_CLK_DIV1 SYS_CLK_DIV0
PWM_MCLK_DIV1
PWM_MCLK_DIV0 PDN_XTAL PDN_OUTPUT_MODE PDN
SYS_CLK_DIV[1:0]
SYS_CLK Clock Divider
00
Use state of MUTE input pin following RST
condition
01
Divide by 2
10
Divide by 4
11
Divide by 8
PWM_MCLK_DIV[1:0]
PWM Master Clock
Divider
00
Divide by 1
01
Divide by 2
10
Divide by 4
11
Divide by 8
