S2-LPQTR datasheet(35/90 Pages) STMICROELECTRONICS

35 / 90 page

S2-LP

Block description

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Figure 6: Direct polar mode

As for the normal TX operations, the TX_FIFO samples are consumed and a management

of the TX_FIFO_THRESHOLD is needed to perform transmissions longer than 128

samples.

The transmission is never automatically stopped and a specific command SABORT should

be given to terminate it.

This function is suitable to implement differential binary phase shift keying modulation

(DBPSK) such as the data modulation used by the SigFox protocol.

5.4.4

Test modes

5.4.4.1

Continuous wave

The device can be programmed to generate a continuous wave carrier without any

modulation. In this way, the carrier will be continuously transmitted until a SABORT

command is sent to the device.

To set the continuous wave the TXSOURCE field (of the PCKTCTRL1 register) must be set

to 0x03.

5.4.4.2

PN9

It is possible to set a Pseudo Random Binary Sequence 9 (PN9) as data source for the

modulator. In this way, these data will be continuously modulated until a SABORT

command is sent to the device.

The TXSOURCE field (of the PCKTCTRL1 register) must be set to 0x03.

5.4.5

Data rate

The data rate programmable is from 0.3 kbps to 250 ksps (see Table 12: "General

characteristics" for further details).

The data rate formula that relates the value of the DATARATE_M and DATARATE_E

registers to the data rate in symbol per second is the following:

Equation 10

– Data rate formula

S2-LPQTR Datasheet(PDF) 35 Page - STMicroelectronics