Hi guys,
I've developed a custom board and I'm thinking about lowering the BOM, so I would like to use only an OTP instead of an external memory on my chip.
Can I change my OTP header after I've burned something into the OTP?
My plan is to burn two different firmwares on my OTP and then change the OTP's header to point to which firmware I want to use on my board. Is this possible? Where can I find more information about it?
Thanks in advance.
Device:
嗨TMiranda,
The OTP on the 585 has a mechanism in order to patch the OTP and replace code using a BISR mechanism with 8 spare rows which will replace the existing data in the OTP (you will find more info about this in the datasheet in paragraph 12.6 BUILD-IN Self Repair), but i dont quite get the scenario, you will burn two different images in the OTP and how exactly you are going to dictate which image should be mirrored from the OTP ? And how re-burning the OTP header will help ?
Thanks MT_dialog
That's exactly it.
I'm planning to burn two different firmwares on my OTP. Since the OTP contents are mirroed in the SysRAM, I was thinking about sending the beginning and last memory address of the first firmware and copy it to the SysRAM.
For some reason, if my firmware goes outdated or I realize that something is wrong, I could re-burn the rest of the OTP with a second firmware and them re-address the used firmware, so what would be copied to the SysRAM is now the second firmware instead of the first one.
That's what I'm wondering if it's possible or not.
嗨TMiranda,
I understood your thinking, but the mirroring of the OTP is done via the OTP DMA and the mirroring procedure and setup of the DMA and the OTP controller is done during booting from the ROM booter. So which address of the OTP will be mirrored in the sysram is hardcoded in the ROM booter, and since you have mentioned the OTP header thats why i am asking which OTP header field you 've noticed that can perform this kind of functionallity, perhaps you have misunderstood any of the OTP header fields.
Thanks MT_dialog
Actually, I thought the header option used for it was the first two addresses (Application Flag 1 and 2), but I guess I'm wrong.
Where can I find more about the OTP? I'm currently using the DA14585 datasheet 2v2 and the User Manual UM-B-083. Is there any other document that I should be looking at?
Thanks.
嗨TMiranda,
Regarding the OTP header only the datasheet includes info regarding this hw of the SoC, you can also have a look at the support portal since there's a new release of the datasheet.
Thanks MT_dialog