LLCC68 datasheet(58/111 Pages) SEMTECH

58 / 111 page

LLCC68

Data Sheet

Rev. 1.1

DS.LLCC68.W.APP

Dec 2024

58 of 111

Semtech

LLCC68

www.semtech.com

hen using Rx Boosted gain, the Rx gain configuration is not saved when entering sleep mode with retention activated. The Rx gain

configuration, and up to 4 additional registers, can be saved when configuring the chip:

• Write 1 (8 bits) to address 0x29F

• Write 0x08AC (16-bit address of the Rx Gain register) to address 0x2A0-0x2A1 msb first

In LoRa mode, command SetLoRaSymbNumTimeout(...) can perform a quick and immediate assessment of the presence (or not) of

LoRa preamble symbols. If the user defined parameter SymbNum is not 0, the modem waits for a total of SymbNum LoRa symbols to

validate, or not, the correct detection of a LoRa packet. If the various states of the demodulator are not locked at this moment, the radio

generates an RxTimeout IRQ. Otherwise, the radio stays in Rx for the full duration of the packet. For more information, see Section 13.4.9

"SetLoRaSymbNumTimeout" on page 93 .

9.7 Transmit (TX) Mode

In TX mode, after enabling and ramping-up the Power Amplifier (PA), the contents of the data buffer are transmitted. The circuit can operate

in different sub-modes: single mode or single with timeout mode.

The timeout in Tx mode can be used as a security to ensure that if for any reason the Tx is aborted or does not succeed (i.e. the TxDone IRQ

never is never triggered), the TxTimeout prevents the system from waiting for an undefined amount of time. Using the timeout while in Tx

mode removes the need to use resources from the host MCU to perform the same task.

In TX mode, BUSY goes low as soon as the PA has ramped-up and transmission of preamble starts.

9.7.1 PA Ramping

The ramping of the PA can be selected while setting the output power by using the command SetTxParams(...).

The PA ramp time can be selected to go from 10s up to 3.4ms.

9.8 Active Mode Switching Time

For active mode switching time details, see Section 8.3.1 "BUSY Control Line" on page 50 .

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