Oscillator driver strength

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User10696
Level 4
Level 4
First solution authored
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.
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3 Replies
jferreira
Employee
Employee
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Hi

I guess they refer to the OSCHPCTRL.GAINSEL.

Regards,
Jesus
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User10696
Level 4
Level 4
First solution authored
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?
3790.attach
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jferreira
Employee
Employee
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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
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