S2-LP datasheet(70/90 Pages) STMICROELECTRONICS

No de pièce	S2-LP

Description	Excellent receiver selectivity and blocking

PDF	90 Pages

Scroll/Zoom	100%

Fabricant	STMICROELECTRONICS [STMicroelectronics]

Site Internet	http://www.st.com

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70 / 90 page

Link layer protocol

S2-LP

70/90

DocID029944 Rev 1

Figure 21: CSMA with persistent mode if channel is busy (timeline)

If the channel is busy and persistent_mode bit is 0, the device will check the channel for the

Tcca period. At the end, being the CS (carrier sense) signal high, it will switch in SLEEP for

a randomic time that can last

�� = �� ∗ (6 + rand(0: 2(��+1)) ∗ (�� + 1)), with

NB=0.

At the end of this period, it will again switch to RX for another Tcca, then sleep and so on

until the number of backoff set is reached. At that point, an interrupt MAX_BO_REACHED

will be notified to the MCU:

Figure 22: CSMA with non-persistent mode if channel is busy (timeline)

Finally, if the channel becomes free (for example during one of the SLEEP times), the

device must assert channel free for a number of NUM._OF_CCA_PERIOD (T. listen)

before transmitting:

Figure 23: CSMA with non-persistent mode if channel becomes free (timeline)

S2-LP Fiches technique(PDF) 70 Page - STMicroelectronics