Oct 08, 2019
08:02 AM
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Oct 08, 2019
08:02 AM
In the Board User's Manual for the CPU_45A CPU Board XMC4500 General Purpose in chapter 2.3 Clock Generation there is the following text:
"The drive strength of the oscillator is set to maximum by software, in order to ensure a safe start-up of the oscillator even under worst case conditions."
I have looked everywhere in the reference manual and data sheet and I cannot find any other information about the drive strength for the external crystals or how the strength can be changed by software.
We have copied the circuit from the evaluation board and the crystal manufactured have measured the drive strength and noticed that it is too strong, so we are very intrested in finding a way (by software) to reduce the strength.
"The drive strength of the oscillator is set to maximum by software, in order to ensure a safe start-up of the oscillator even under worst case conditions."
I have looked everywhere in the reference manual and data sheet and I cannot find any other information about the drive strength for the external crystals or how the strength can be changed by software.
We have copied the circuit from the evaluation board and the crystal manufactured have measured the drive strength and noticed that it is too strong, so we are very intrested in finding a way (by software) to reduce the strength.
3 Replies
Oct 09, 2019
12:03 AM
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Oct 09, 2019
12:03 AM
Hi
I guess they refer to the OSCHPCTRL.GAINSEL.
Regards,
Jesus
I guess they refer to the OSCHPCTRL.GAINSEL.
Regards,
Jesus
Oct 09, 2019
01:49 AM
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Oct 09, 2019
01:49 AM
This is the register I expected to find the control, but according to the current Reference Manual (V1.6, 2016-07), this register does not have any GAINSEL bits.
Is the documention incorrect, or does not XMC4500 not have these bits?
Is the documention incorrect, or does not XMC4500 not have these bits?
Oct 10, 2019
09:03 AM
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Oct 10, 2019
09:03 AM
Hi,
The XMC4500 does not provide this possibility. I was confused with XMC47/XMC48 which does offer this possibility.
Did you try increasing the external damping resistor?
Regards,
Jesus
The XMC4500 does not provide this possibility. I was confused with XMC47/XMC48 which does offer this possibility.
Did you try increasing the external damping resistor?
Regards,
Jesus