Selecting RF Parameters thru SmartRF Studio

Saycoda

I need a refresher on how the "Code Export" works with SmartRF Studio, so as to test various RF parameters and modulation schemes.

There are 3 selections in the EasyLink_init() modulations; 50bps2GFSK, 625bpsLRM, & Custom. Am I to assume the command arrays for the first two comes from the file \Easylink\smartrf_settings_predefined.*, and that if I use Custom the commands come from \smartrf_settings\smartrf_settings.*

I have a custom project that is based on the simple Easylink TX/RX examples and want to try various modulations for performance. When I select the modulation as 50bps2gfsk the project works fine. When I export a flavor of LRM (not 625bps) and call the files "smartrf_settings.*" and select Custom modulation, the prject does not work.

Any help would be appreciated.

over 7 years ago

0 Richard W. over 7 years ago

TI__Genius 14860 points

Hi Saycoda,

I don't see an error in your description. Do your exported settings work with the rfPacket examples? Can you tranmsit/receive packets with SmartRF Studio?

0 TER over 7 years ago in reply to Richard W.

TI__Guru**** 317180 points

What do you mean by " a flavor of LRM"? As Richard W points out, have you tested that the configuration actually works in SmartRF Studio before you exported the code?

0 Saycoda over 7 years ago in reply to TER

Expert 1580 points

A "flavor of LRM" means deviating from the canned settings of SmartRF Studio, i.e. the 625bps LRM has a Symbol rate of 10K, I may want to vary that to 50K for example.

Thanks

0 Siri over 7 years ago in reply to Saycoda

TI__Guru* 79441 points

When using LRM, max symbol rate to program is 40 ksps. The FEC will reduce the max bit rate to 20 kbps.

Default the spreading is set to 8:

// override_phy_lrm_rom_dsss8.xml

// PHY: Configure DSSS=8

HW_REG_OVERRIDE(0x505C,0x073C),

This can be changed to 4, 2 or 1 by modifying this override

HW_REG_OVERRIDE(0x505C, 0x0303), // 4

HW_REG_OVERRIDE(0x505C, 0x0100), // 2

HW_REG_OVERRIDE(0x505C, 0x0000), // 1

Siri

0 Nikhil Kant over 7 years ago in reply to Siri

Expert 1130 points

How will changing DSSS affect the range

0 Sverre over 7 years ago in reply to Nikhil Kant

TI__Mastermind 39860 points

For the same symbol rate, increasing the DSSS spreading (2, 4 or 8) will give reduced data rate and improved sensitivity.

Example:
20 ksps with spreading 8 gives a bit rate of 1.25 kbps and a sensitivity of -121 dBm
20 ksps with spreading 2 gives a bit rate of 5 kbps and a sensitivity of -119 dBm

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Selecting RF Parameters thru SmartRF Studio