[riot-commits] [RIOT-OS/RIOT] 49fda3: cpu/samd5x: don't run DFLL on-demand

Dylan Laduranty noreply at github.com
Fri Apr 3 17:18:50 CEST 2020


  Branch: refs/heads/master
  Home:   https://github.com/RIOT-OS/RIOT
  Commit: 49fda3e9005f745cd4f00fe628c8687bcbaff35d
      https://github.com/RIOT-OS/RIOT/commit/49fda3e9005f745cd4f00fe628c8687bcbaff35d
  Author: Benjamin Valentin <benpicco at googlemail.com>
  Date:   2020-04-02 (Thu, 02 Apr 2020)

  Changed paths:
    M cpu/samd5x/cpu.c

  Log Message:
  -----------
  cpu/samd5x: don't run DFLL on-demand

The DFLL on samd5x has a hardware bug that requires a special
re-enabling sequence when it is disabled and then re-enabled again.

When running the clock on-demand, the hardware handles the disabling
and re-enabling so that sequence does not get executed.

To reproduce, run `tests/periph_uart` on `same54-xpro`.

Without this patch the test will get seemingly stuck on `sleep_test()`.
(In fact it keeps running, but the DFLL has the wrong frequency so the
UART baudrate is wrong).

In this test, on `same54-xpro` only UART0 is sourced from DFLL.
So if the UART is disabled the DFLL will be turned off as well.


  Commit: 3b34768eafd390b4b82f9f7f37eb221cbc3101e7
      https://github.com/RIOT-OS/RIOT/commit/3b34768eafd390b4b82f9f7f37eb221cbc3101e7
  Author: Dylan Laduranty <dylan.laduranty at mesotic.com>
  Date:   2020-04-03 (Fri, 03 Apr 2020)

  Changed paths:
    M cpu/samd5x/cpu.c

  Log Message:
  -----------
  Merge pull request #13796 from benpicco/cpu/samd5x/dfll_no_ondemand

cpu/samd5x: don't run DFLL on-demand


Compare: https://github.com/RIOT-OS/RIOT/compare/942c63eb399a...3b34768eafd3


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