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Can't get clock data on CKO1/PTB10.

Question asked by John Clarke on Oct 15, 2015
Latest reply on Oct 22, 2015 by alejandrolozano



I have a SVF321R3CKU2 that I would like to measure some of the clock speeds using CKO1 on PTB10.  I have configured the CCM_CCOSR  register to enable CKO1, set the divisor to /4 and selected the A5 Core for the output.  With the current clock setting the A% clock should be running at 264 MHz.  I have also configured the IOMUXC for PTB10 to select the CKO1 ALT6.  I am using a debugger and verified the following settings:


PTB10: 0x005028C6


SPEED: Medium – 100MHZ

SRE: Fast

ODE: Disabled

HYS: Disabled

DSE: 50 Ohm/80 Ohm

PUS: 100 kOhm Pull Down

PKE: Disabled

PUE: Pull

OBE: Enabled

IBE: Disabled


CCM_CCOSR: 0x000004FD

CKO1_EN: Enabled

CKO1_DIV: /4

CKO1_SEL: CA5 core clock


However I get no output on PTB10/CKO1.  Am I missing a configuration item?  Any help would be appreciated.


Thanks you,

John Clarke


Message was edited by: John Clarke Just realized I labeled the registers wrong in the initial post, sorry for any confusion.