yul mama

firmware update over the air

Discussion created by yul mama on Oct 22, 2009
Latest reply on Aug 5, 2010 by Shivashankarayya V Salimath

Hi all,

I'd like to update my microcontroler firmware via GPRS. I've an external I2C memory. My GSM modem has already an IP stack. I just need to transfer some bytes on the GSM UART and it arrives on the server side. No matter about TCP/IP.

The problem for me is GPRS technology and the protocol to implement between the microcontroler and the server.

Is it better to transfer 100 bytes packets or 1500 ?  consider that sometimes the GPRS quality could be poor.

MTU (max transmit unit) =1500 bytes on this modem.

When the server transfer the 1500bytes to my microcontroler, would you add an ACK ? then send a new 1500Bytes frames ?

Would you add CTS/RTS hardware flow control ?

Would you add some CRC, checksum to check the integrity ?

Zmodem ?  encryption needed ? compression is a plus ?

I'd like to have a standard protocol and not doing my protocol.

 

Anyone implemented a binary difference patch on 8bit microcontroler ? the lower data, the less GPRS cost.

Regards,

yul

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