CODEWITHSUNDEEP
msp430
Sandeep Reddy Goli
Sandeep Reddy Goli

Reputation: 202

How to measure clock frequency of C430F5137 using programming

I am using CC430F5137 system on chip.From the data sheet I got to know it uses 26MHz clock for the radio. To verify that,How do I measure the radio clock frequency by using MSP430 programming?

Any suggestions please....

Is there any timer/counter that is connected to radio clock?

Thanks.

Upvotes: 2

Views: 1357

Answers (2)

Gauthier
Gauthier

Reputation: 41985

To measure the RF clock (26 MHz) with an oscilloscope, you need to:

1 - output the clock from the radio module to the core, e.g. through the signal GDO1 (internal signal between the RF SoC and the core). To do that, adjust the corresponding value in the RF config table, see 25.3.5 of the CC430 family user guide. To use GDO1, put 0x30 (RFCLK/1) in IOCFG1. See Table 25-21 if you need other dividers than 1 (depending on the limitations of your measuring equipment).

2 - map the radio module's signal GDO1 to a free IO pin.

PMAPKEYID = PMAPKEY;    // Get write-access to port mapping regs
P2MAP6 = PM_RFGDO1;     // Map radio GDO1 to output pin 2.6.
PMAPCTL |= PMAPRECFG;   // Allow for future port map configurations.
PMAPPWD = 0x00;         // Lock Port mapping

Set also the SEL and the DIR bits for the IO pin you are using.

3 - an oscilloscope (or frequency counter) that can measure 26 MHz accurately enough for your needs.

Note: measuring MCLK might not be accurate enough, its generation going through other disturbing stuff such as FLL...

Upvotes: 1

bblincoe
bblincoe

Reputation: 2483

The CC430 family (similar to the other MSP430 family) can output its MCLK (or SMCLK) signal through a GPIO configured for that operation. MCLK is the same clock used for the radio peripheral. This is the signal you would want to measure on an oscilloscope.

The CC430 specifically has a port mapping controller designed to mux these functions to a designated GPIO. If you take a look at the CC430 Family User's Guide (http://www.ti.com/lit/ug/slau259e/slau259e.pdf), section 9 outlines the port mapping controller. Also, use the datasheet (http://www.ti.com/lit/ds/symlink/cc430f5137.pdf) to determine how the PxSEL and PxMAP registers must be configured for this secondary GPIO function - this can generally be found in the "input/output schematics" section.

The following is not the exact solution, but should be a guide for you. Please take a look at the following forum post: http://e2e.ti.com/support/microcontrollers/msp430/f/166/t/19075.aspx

Upvotes: 0

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