Frankly Exasperating, TI.

April 11, 2011 1:01 AM

In a FET (Flash Emulation Tool), what exactly is being emulated?

I've been playing around with various TI MSP430 MCUs, and have yet to see any explanation of why they call their programmers "FET"s. Is this just a historical reasons thing, or is the programmer actually emulating something in order to write to the MCU flash?

posted by russm to Technology (4 answers total)

I think there may be some emulation involved to facilitate the device's debugging features, although I don't know the details. Probably no emulation involved in the actual writing of the flash.
posted by Diplodocus at 1:26 AM on April 11, 2011

Best answer: As I understand it, it's called an emulator because it's meant to completely replace the actual 430 chip during development, also know as In Circuit Emulation (ICE). In other words, with a simple dumb flasher, what you would do as you're testing your code is take the 430 out of the product being tested, put in in the flasher, flash the latest version of the code, take it out of the flasher, put it back in the product, turn on the product, test product, and repeat. With an emulator you just plug the emulator's outputs into the socket where the 430 would normally go and now you can do as many compile/download/test cycles as you need without ever having to physically remove anything. When you've got all the bugs worked out you remove the emulator and put an actual 430 in the product so that it's standalone.
posted by Rhomboid at 2:58 AM on April 11, 2011

Oh and I forgot the most important part -- because it's emulating a 430 and it's connected to both the computer and the product at the same time, you can do cool stuff like single-stepping, setting breakpoints, inspecting memory, etc. while the product is live because the 430 is being emulated.
posted by Rhomboid at 3:00 AM on April 11, 2011

Response by poster: Rhomboid - yeah OK, that makes sense. "Flash/Emulation Tool" rather than "Flash Emulation Tool", since it also provides ICE. (That also fits with the FET interfacing to the MCU over JTAG or Spy Bi-Wire)

(Of course ICE is a historical reasons name these days anyway, what with JTAG giving you access to on-chip debug support rather than actually doing emulation.)
posted by russm at 3:24 AM on April 11, 2011