Could you explain me which way of PLL setting for BF527 is correct?
There is information:
"Note that the divisor ratio must be chosen to limit the system
clock frequency to its maximum of fSCLK. The SSEL value can be
dynamically changed without any PLL lock latencies by writing
the appropriate values to the PLL divisor register (PLL_DIV)
using the bfrom_SysControl() function in the on-chip ROM."
ADSP-BF522/ADSP-BF523/ADSP-BF524/ADSP-BF525/ADSP-BF526/ADSP-BF527: Blackfin Embedded Processor Data Sheet (Rev D, 07/2013) (pdf, 6193 kB)
But there is also anomaly: 05000440 - bfrom_SysControl() Cannot be Used to Write the PLL_DIV Register.
So, is this anomaly still valid or not (for rev.0.2)?
Could you inform me also when frequency changing process starts?
When idle instruction is issued or write to any PLL (PLL_DIV, PLL_CTL, PLL_LOCKCNT) register triggers it?
All anomalies are described in the same style in the anomaly sheet:
APPLIES TO REVISION(S)
PLL_DIV and PLL_LOCKCNT can be written on the fly and take effect immediately.
PLL_CTL and VR_CTL need the idle instruction to trigger the PLL/Voltage change written to the register.
Can I use bfrom_SysControl() for changing PLL_DIV register for BF527 rev.02 as it is stated in: Blackfin Embedded Processor Data Sheet (Rev D, 07/2013) ?
I'm afraid not since anomaly 05000440 applies to BF527 rev 0.2. PLL_DIV must be changed by modifying the register directly rather than using bfrom_SysControl().