Measuring Gains
The goal of this section is to find four gain values, TRSW_RX, the LNA lod, the LNA value and the PGA Value. The maximum RX Gain is required. If this is a negative value, use 0 instead.
After using the tables below to check the values:
If the LNA lod value is 0
AND Radio Register 0x7A with 0xFFF7
- Otherwise
OR Radio Register 0x7A with 0x8
Loopback Gain Enabled
- If using the TRSW_RX value is desired
Take the TRSW_RX Gain (in hdB, from Loopback Gain measurement) and divide by 2
- If the maxmimum Gain value is greater or equal to the result
- Subtract the result from the maximum Gain value, this value will be referred to as the TRSW_RX Gain
The TRSW_RX value is 0x20
- Otherwise
- The TRSW_RX Gain is the maximum Gain value
The TRSW_RX value is 0
If the TRSW_RX Gain is < 9
The LNA lod value is 0
- Otherwise
The LNA lod value is 1
- Subtract 0x8 from the TRSW_RX Gain value
- Clamp the TRSW_RX Gain value between [0, 0x2D]
Divide the TRSW_RX Gain value by 3 to find the PGA Value
If the PGA Value is 5 or greater
Subtract 5 from the PGA Value
The LNA Value is 2
- Otherwise
The LNA Value is 0
Loopback Gain Disabled
TRSW_RX |
0x20 |
LNA Value |
0 |
The other values depend on the maximum RX gain as shown below:
Maximum RX Gain |
LNA lod |
PGA Value |
>= 0x14 |
1 |
2 |
0x14 > x >= 0x12 |
1 |
1 |
0x12 > x >= 0xF |
1 |
0 |
0xF > x |
0 |
0 |