topic Re: TX/RX switching time of MMAC in Wireless MCU

TX/RX switching time of MMAC

Johnny9 — Thu, 15 Sep 2022 08:57:54 GMT

I am developing with JN5189 and Micro MAC library.

I have one problem.
When I try to send and receive packets using the MMAC functions(vMMAC_StartPhyTransmit() and vMMAC_StartPhyReceive()), TX/RX switching time is more than 3.5(ms). This causes the problem that the ACK packet cannot be received.
TX/RX switching time of about 3.5(ms) is the maximum performance of Micro MAC? Can I shorten this time to less than 1.5 ms?

Re: TX/RX switching time of MMAC

EduardoZamora — Thu, 15 Sep 2022 17:07:56 GMT

Hello @Johnny9,

Hope you are doing well.

Could you please confirm that you are following the ZigBee Green Power (for ZigBee 3.0) User Guide [JN-UG-3134]? This guide can be found inside the JN5189 SDK folder > docs > wireless > Zigbee. Please, take a look at Chapter 3: MicroMAC Stack for Green Power.

Also, please consider that one of the disadvantages of PHY mode is that automatic acknowledgement is not available. In order to enable this option, it is preferable to use MAC mode instead. MAC and PHY Transceiver Modes are described in Chapter 3.6.

Regards,
Eduardo.

Re: TX/RX switching time of MMAC

Johnny9 — Fri, 16 Sep 2022 10:19:21 GMT

Hello @EduardoZamora,

I didn't find the answer I was looking for in the User Guide [JN-UG-3134].

(Also, I'm well aware that autoack is not supported in PHY mode.)

The problem is that after sending a packet I cannot receive another packet for 3.5ms.

Any ideas on how to receive an incoming ACK packet immediately after sending a packet?

Or is there no way due to the limitations of the MMAC library?

The example I referenced is JN-AN-1261, and I tested it like this:

APP_RADIO_vTx(FALSE);
if (APP_RADIO_bRx(TRUE, 40))
{
/* Process Received frame */
}
else
{
PRINT("No Packet\n");
}

Thank you.

Re: TX/RX switching time of MMAC

EduardoZamora — Mon, 19 Sep 2022 22:47:34 GMT

Hi,

I apologize for any inconvenience this might cause you, these time constraints are due to the MicroMAC Library implementation.

Regards,
Eduardo.

Re: TX/RX switching time of MMAC

Johnny9 — Fri, 23 Sep 2022 07:50:42 GMT

Hi,

What I was wondering about has been solved.

(Maybe I'll have to find another way.)

Thanks for your reply.

Regards,

Johnny9

Re: TX/RX switching time of MMAC

Johnny9 — Tue, 27 Sep 2022 09:09:23 GMT

If so, isn't the MicroMAC library backwards compatible with IEEE802.15.4 MAC?
That is the time exceeding IEEE802.15.4's macAckWaitDuration(0.864ms).