How to output cc2540 32k crystal signal to an pin for measurement?

user4427404

Other Parts Discussed in Thread: CC2540, CC2640, Z-STACK

I want test the 32k crystal accuracy about my cc2540 board.
I found cc2640 can use following code to output 32k clock to an PIN for measure. Can some one tell me how to output cc2540 32k crystal to an PIN?
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HWREG(0x40094010) = 0; // Enable clock output to AON_32k
HWREG(0x40081000 + 4*IOID_27) |= 7; // Connect IOID27 (LED2 on 7x7) to AON_CLK32K (works for any IOID)

Thanks.

over 8 years ago

0 Igor Sherer over 8 years ago

Guru 31280 points

Hi,

What is the firmware framework? is it Z-stack?

Anywho, according to cc254x User's Guide, section 7.10, in order to output the 32KHz clock to any of the P0 pins, one should do the following:

/*Configure the output pin - in this case I've chosen P0.1*/
PMUX &= ~0x70; /* Clear CKOPIN bits */
PMUX |= 0x10; /* Set P0.1 as output pin for 32KHz clock */
/* Enable 32KHz clock output */
PMUX |= 0x80;

Just make sure there no other code which later disables the clock output.

0 user4427404 over 8 years ago in reply to Igor Sherer

Prodigy 70 points

I test it with your provided code, it works perfect. Thank you very much.

0 Igor Sherer over 8 years ago in reply to user4427404

Guru 31280 points

Great, glad it worked out for you.

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How to output cc2540 32k crystal signal to an pin for measurement?