lab11 / signpost

Exploring what happens when you put computers on sign posts.
Apache License 2.0
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Possible Reset Clock Issues #69

Open adkinsjd opened 7 years ago

adkinsjd commented 7 years ago

I am experience a problem on the microwave radar board where spurious resets occur if the clock in tock is set to 16MHz. Touching the reset line/adding any capacitance seems to solve the issue. Notable changing the clock seems to change the pull up resistance on the SAM4L from 30kohm to 25kohm. This problem is unresolved - clocks should be set to 48MHz to not experience the problem.

We tried to solve the problem by writing the PPCR register of the SAM4L to 0x1FF instead of 0x1FE to "enable the reset pullup". That seems to disable the reset pullup instead and did not solve the issue.