what happens if I exceed the maximum f(core)?
I'm working with an ADAU1445, and it looks like I accidentally set PLL[2..0] = 0, for 64x f(core), but applied 12.288MHz, which should be 256x. So the core might try to run way pass max. I corrected it (hardware bug) but now the chip seems unresponsive. Could be unrelated. So I'm wondering if setting the PLL this way and applying an overspeed clock can actually damage the silicon? (btw in debugging I did enable the clocks and attempt to download, start, etc.)
Audio Signal Processors
adau1445
SigmaDSP Audio Processors
Hi bowerymarc,
Sorry that it took me a few days to get back to you.
I don't think overclocking the device would damage the device in any way. Actually, I'm surprised that the PLL was even able to lock to the clock when it was using the wrong predivider. I would expect the PLL to not lock and the device to just sit there idly.
Perhaps the unresponsive nature of the device is due to damage or loose solder joints?
A good test to see if the comm port and memories are alive would be to try reading back some registers you've written and check if the values match. Then, if you try to run a program, put a DC source in it connected to a DSP readback cell. You can write to the DC source and read from the DSP readback cell to see if the program is successfully transferring the data from one memory location to the other.
So if the PLL wouldn't lock, would it just not run at all, or run at a slower speed, or just misbehave if you tried to access the registers?
I tried configuring the clock out to clock/245 and it tracks the input (I mistakenly thought it was PLL output/256). So it seems you can't monitor the PLL unless you can get a program in there and output some bit clocks...
Yes, it could be solder etc... I'm checking on that.
I haven't gotten the the point of being able to load a whole program. Sometimes the unit will NACK when I try to access a register. But not always. Very odd. I'm having a second board built up to compare and I'll get back to you....
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Thank you,
EZ Admin
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