Talk:FOSS Programmer

mcmaster

While I'm not opposed to such a project, I'm skeptical of the time that it will take to develop such a device and the availability of it vs a COTS solution. In particular, with a TL866 costing $50 and still readily available, effort is much better spent focusing on these.

"Nominal max VPP is 21V on the TL866 A/CS and 18V on the TL866II." [Elemecca]. Did this cause any important devices to be discontinued?

cr1901

While the TL866 is ending production, the TL866-II is still available/produced. In case TL866-II stops production and both variants become difficult to obtain easily, doing our own design has been proposed before. The short version is we have a lot of good/doable ideas for a FOSS programmer, but it would be a time commitment and would not be as cheap as a TL866. I suspect in principle an open design would attract more contributors in the long run; while Elemecca has done a great job on this front, PIC isn't exactly known to be pleasant to work with.

The basic idea I've seen thrown around for a FOSS programmer (from talking with davidc__ on siliconpr0n IRC channel) is thus:

• Use an FPGA with a custom I2C core, possibly an FPGA USB core as well. If we can tolerate HDL to provide a base that's rarely modified, this reduces part count while maximizing flexibility.
• The I2C interface talks to a number of Silego Greenpak 4s, which control both the pass transistors for the power lines and also provide lines of I/O for the target device.
• Greenpak 4 interfacing gives us "free 5V support", they are also incredibly cheap and small.
• FPGA can be put to other use? My proposal is a softcore (RISC-V? lm32? Something else?) running from SPIflash and using block RAM and RAM. This would give a superior development environment in terms of resources 'and' toolchain support compared to PIC.

I like the idea of RISC-V on FPGA as a base, especially since gcc supports RISC-V now, as long as it uses a very popular FPGA. I'm a bit less enthusiastic about Greenpak -- mainly because I don't know anything about it. Like, are they in the habit of discontinuing chips older than like 5 years? --Robertbaruch (talk) 22:46, 29 December 2018 (UTC)