Hi,
One of my Customers has the following problem regarding the AM1808.
Please look into this. I will direct my Customer to this Forum for further discussions, if required.
Thanks in advance.
I am having problem with USB 1.1 host after a transition to operating point (frequency). Initially everything works well. After my power management system switches the operating frequency USB 1.1 host stops sending any data on bus.
Following are details:
SOC AM1808exp
Board Logic PD
Zoom™ AM1808 Development Kit
Steps Needed to Recreate Problem:
The system is initially configured to use the following values, mentioned in the table
PLL0_SYSCLK1 = 600Mhz
PLL0_SYSCLK6 = 600Mhz
PLL0_SYSCLK2 = 200
PLL0_SYSCLK4 = 150
After some time for power saving the PLL 0 multiplier value is changed to 0x0C in PLL 0 Multiplier Control Register (PLLM). The values in the PLLDIVn registers of PLL0 are kept intact. After frequency transition the I/O request submitted on the OHCI controller(USB1.1) does not appear on bus but OHCI registers are read /write correctly.
As far as USB clocking is concerned the USB1.1 clock source is 48MHz clock obtained from the USB2.0 PHY. The CFGCHIP2 registers is configured to use the AUXCLK for USB0PHYCLKMUX and 48Mhz clock form USB2 PHY for USB1PHYCLKMUX.
The USB1.1 subsystem bus clock is fed by the PLL0_SYSCLK4. This clock is scaled by the PLLM register value.
