LLCC68 datasheet(68/111 Pages) SEMTECH

68 / 111 page

LLCC68

Data Sheet

Rev. 1.1

DS.LLCC68.W.APP

Dec 2024

68 of 111

Semtech

LLCC68

www.semtech.com

13.1.4 SetTx

The command SetTx() sets the device in transmit mode.

• Starting from STDBY_RC mode, the oscillator is switched ON followed by the PLL, then the PA is switched ON and the PA regulator starts

ramping according to the ramping time defined by the command SetTxParams(...)

• When the ramping is completed the packet handler starts the packet transmission

• When the last bit of the packet has been sent, an IRQ TX_DONE is generated, the PA regulator is ramped down, the PA is switched OFF

and the chip goes back to STDBY_RC mode

• A TIMEOUT IRQ is triggered if the TX_DONE IRQ is not generated within the given timeout period

• The chip goes back to STBY_RC mode after a TIMEOUT IRQ or a TX_DONE IRQ.

The timeout duration can be computed with the formula:

Timeout duration = Timeout * 15.625µs

Timeout is a 23-bit parameter defining the number of step used during timeout as defined in the following table.

The value given for the timeout should be calculated for a given packet size, given modulation and packet parameters. The timeout behaves

as a security in case of conflicting commands from the host controller.

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.

Table 13-6: SetTx SPI Transaction

Byte

1-3

Data from host

Opcode = 0x83

timeout(23:0)

Table 13-7: SetTx Timeout Duration

Timeout(23:0)

Timeout Duration

0x000000

Timeout disable, Tx Single mode, the device stays in TX Mode until the packet is transmitted and returns in

STBY_RC mode upon completion.

Others

Timeout active, the device remains in TX mode, it returns automatically to STBY_RC mode on timer

end-of-count or when a packet has been transmitted. The maximum timeout is then 262s.

LLCC68 Datasheet(PDF) 68 Page - Semtech Corporation