In application programming

abellinger · ‎2008-09-03

Posted on September 03, 2008 at 15:17

abellinger · ‎2011-05-17

Posted on May 17, 2011 at 11:32

Hello all:

I am new to ST and ARM MCU's and am looking at them due to some of the ST9's being available with 2048K program space & ethernet/usb. My past experience is with 8051's.

One feature I would really like to implement is firmware upgrades from USB memory sticks. (If a certain file name is located on the root of the memory stick, the MCU will reboot from 128K code space, copy the file to the 2048K space, and switch back to 2048K as default boot location).

My understanding of the IAP process though is that JTAG must still be involved at some level, to change the boot sector (because this can only be modified through JTAG and not code). Is this true? I can not expect customers to have to open up equipment and write to sectors with debuggers to upgrade firmware.

Even if doing this requires me to have a second small MCU to write the JTAG commands to switch the boot sector, I would consider this in my design. Does anyone have any thoughts on this or know of any reference designs that utilize this kind of scheme?

Thanks,

Andrew

abellinger · ‎2011-05-17

Posted on May 17, 2011 at 11:32

An update - this is taken from page 54 of 13495.pdf

Optional configuration

Using the STR91xFA device configuration software tool, or IDE from 3rd party, one can specify that the smaller secondary Flash memory is at the boot location at reset and the primary Flash is disabled. The selection of which Flash memory is at the boot location is programmed in a non-volatile Flash-based configuration bit during JTAG ISP. The boot selection choice will remain as the default until the bit is erased and re-written by the JTAG interface. The CPU cannot change this choice for boot Flash, only the JTAG interface has access.