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Hello all,
We are looking for a drop in replacement part for TMS320E25 (TMS320E25 went obsolete long time ago) and looks like TMS320C25 can be a candidate because it is still available at sites like Mouser, DigiKey, and Newark, however, TMS320E25 comes with EPROM which we can program here at the factory, but there is no information on the datasheet on how to program TMS320C25 which comes with ROM. So my question is: how is programming on TMS320C25 done? Can we buy a programmer what would do it? or do we buy the chips and then send it to TI with the program and then TI programs it? or do we have to order brand new chips from TI and they are programmed while they are being made? If the last one is true why would vendors sell those ICs? because without the program the are pretty much useless
Any information will be helpful Thank you
-Andrey
Andrey,
The C25 is a factory ROM device, as you noted. The ROM is programmed by TI at manufacturing time. The standard ROM includes a bootloader, and customers would use this bootloader to load up the internal RAM or external RAM from an I/O or the serial port. Alternately, you can begin execution directly in an external EEPROM if interfaced on the memory interface. This is why the C25 is available from distribution.
Some users did have a custom ROM mask done and put their own code into the ROM, but this required a custom CMOS ROM mask and there was an NRE fee and minimum purchase quantity associated with this. I do not know the specifics of the NRE or quantities for this specific device, nor do I know if TI is even still accepting new customers on this device (versus existing customers who long ago had the ROM mask made up for them and it sits in storage someplace at TI). The C25 is some 30 years old at this point. The custom ROM was generally only available to higher volume customers, since as I said there was a minimum order quantity and NRE fee. I suspect your distributor could look into the details of this for you.
Regards,
David