Esb Packet gap issue and packet “mtu”

RE: Esb Packet gap issue and packet “mtu”

Håkon Alseth — Mon, 17 Oct 2022 07:43:23 GMT

Hi,

1. Don't print in the event_handler. This applies to both PRX and PTX project.

This is because the default setting is that you log in-place.

You can override this by setting:

"CONFIG_LOG_MODE_DEFERRED=y"

2. Your PTX seems to send only when flag "ready" is set. However, the main loop also includes a k_sleep():

if (ready) {
	/* Send logic here */
}
k_sleep(K_MSEC(1000));

Try changing the k_sleep(..) to a k_cpu_idle() call instead.

Kind regards,

Håkon

RE: Esb Packet gap issue and packet “mtu”

sean — Mon, 17 Oct 2022 02:02:54 GMT

Hi,

According to your modification, 252 bytes work fine。On the tx side, I'm sending data in the send success callback, which is a huge gap every 252 bytes，About 6.7 ms，How to reduce every 252 bytes gap？As shown in the picture below

RE: Esb Packet gap issue and packet “mtu”

Håkon Alseth — Fri, 14 Oct 2022 10:12:10 GMT

Hi,

[quote user=""]①On the ptx side, packets are sent twice in a row；At the receiving end, the packet gap is about 8 milliseconds。How much milliseconds the esb minimum packet gap ?How to reduce packet gap？[/quote]

The time for one transaction depends on the packet length. If your overall on-air payload is 250 bytes, the calculation is:

Tramp-up + Tpayload = 130 us + 250 bytes * 8 bit * 1/2Mbit = 1130 us.

You'll also have to account for the ACK from the PRX.

[quote user=""]②Use the maximum 252 packets to send it return “Payload write failed, err -122”，esb_start_tx() it retun -61，It took many days to debug there is no progress，The attachments are code and configuration[/quote]

ptx/src/main.c::154 sets the payload length to 126. Try setting this to 252.

Also, you should set the .protocol to "ESB_PROTOCOL_ESB_DPL" and consider using 2 byte CRC. This change must be applied to both PRX and PTX.

Kind regards,

Håkon