Hello,
I see that the RF studio, Easylink, etc., come with pre-defined values for the .txPower member of CMD_PROP_RADIO_DIV_SETUP that match given dBm values.
My question is what is the meaning of the .txPower and how can I trim this to custom designs?
Looking at the pre-defined values, I guess there must be some bit fields in this uint16 value, but I can only guess. The rf_prop_cmd.h header file's comment stays quiet about this.
Can you clarify please?
BR,
Harald
The parameter txPower contains temp. coefficient setting, gain setting, IB setting and the TX BOOST bit:
txPower[15:9]: temp coefficient
txPower[8]: TX BOOST bit
txPower[7:6]: Gain
txPower[5:0]: IB
I recommend that you read about it in the technical reference manual (TRM), section 23.3.4.16 (and more) to get the concepts of this parameter.
It is possible to generate your own, custom Tx power table for your application, where the aim is to output constant Tx power over temperature. The temperature coefficient is applied to automatically compensate the IB setting based on the temperature readout of AON_BATMON_TEMP.
There are three different gain settings and for each gain setting the IB can be adjusted from 0x0 to 0x3F resulting in 64*3 = 192 available settings for TX output power. The temperature coefficient is given as an input in addition to the requested gain and IB setting.
Based on the readout from the temperature sensor and the temperature coefficient setting the IB is adjusted.
In addition you also have the TX boost bit.
A custom TX power table should be generated by the following method (to obtain constant Tx power over temperature for a certain Tx parameter value):
Step 1: Room temp setting: Adjust the gain and IB setting to get the requested output power level at room temperature with temperature compensation disabled. This setting will be the Ib_requested.
Step 2: Low temp setting: Use the same gain setting and adjust the IB setting to get the closest output power level from step 1 at low temperature. This setting will be the Ib_low_temp
Step 3: High temp setting: Use the same gain setting and adjust the IB setting to get the closest output power level from step 1 at high temperature. This setting will be the Ib_high_temp
Step 4: Calculate temp coefficient. Use the IB settings from the low and high temperature measurements to calculate the temperature coefficients. The temp coefficient is based on a linear approximation between the two temperature extremes and calculated as follows:
Repeat step 1-3 for all the desired power levels
