LLCC68 datasheet(38/111 Pages) SEMTECH

38 / 111 page

LLCC68

Data Sheet

Rev. 1.1

DS.LLCC68.W.APP

Dec 2024

38 of 111

Semtech

LLCC68

www.semtech.com

The RSSI gain can be calibrated using the registers described in Table 6-4. By default, the chip is calibrated for the 868-915MHz band on the

LLCC68 EVK.

Gain Tune and Gain Offset values can be determined using an RF generator with the LLCC68 hardware implementation as follows:

1. Setup the device in GFSK mode and set the desired RF frequency.

2. Setup the device in manual gain mode (disable the AGC (Auto Gain Control)).

3. Use SetRssiCalibration API to set all tunes and offsets to 0.

4. Loop through all the different gains, including LNA boost mode (high power mode):

a. Use the generator to emit a continuous tone at a specific output power gen_pwr (gain dependent), and account for all cable

losses. A direct connection is recommended.

b. Read the instantaneous RSSI (rssi_inst).

c. Calculate the rssi_error = rssi_inst - gen_pwr.

d. Log the rssi_error in a file.

5. Find the common offset between all errors, and use it as the new global offset.

6. Find the individual errors (relative to the new global offset) and use them as the tunes.

7. Write the RSSI Calibration register values, and go though the main loop again to check that the instantaneous RSSI is now calibrated.

Table 6-4: Registers and Values

Name

Address

Bits

EVK

470-490MHz Band

EVK

868-915MHz Band

Data

AgcRssiMeasCalH

0x89c

4:0

0x01

AgcRssiMeasCalL

0x89d

7:0

0x27

0x53

AgcGainTune_1_2

0x8f5

7:4

0xD

0x0

AgcGainTune_1_2

0x8f5

3:0

0xE

0x0

AgcGainTune_3_4

0x8f6

7:4

0xE

0x0

AgcGainTune_3_4

0x8f6

3:0

0x2

0x0

AgcGainTune_5_6

0x8f7

7:4

0x3

0x0

AgcGainTune_5_6

0x8f7

3:0

0x2

0x0

AgcGainTune_7_8

0x8f8

7:4

0x4

0x0

AgcGainTune_7_8

0x8f8

3:0

0x4

0x0

AgcGainTune_9_10

0x8f9

7:4

0x3

0x0

AgcGainTune_9_10

0x8f9

3:0

0x3

0x0

AgcGainTune_11_12

0x8fa

7:4

0x3

0x0

AgcGainTune_11_12

0x8fa

3:0

0x4

0x0

AgcGainTune_13

0x8fb

3:0

0x4

0x0

AgcGforstPowthr

0x8b9

7:0

0x4

0xA

AgcSensiAdjust

0x8ac

7:2

0x22

0x25

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