Parse the required SCPI commands

[scy]

• FREQuency or PERiod for the base clock
• CHANnel#:NUMerator and CHANnel#:DENominator to set the multiplier for a channel
• CHANnel#:DELay to set the delay/phase
• CHANnel#:WIDth for the pulse width

Note that we’re not using USBTMC for this first iteration, but simple CDC (“USB serial”).

[scy]

A problem has come up: We were planning to use Vrekrer_scpi_parser, a C++ library, to parse the SCPI commands in the firmware.

When trying to add the library to the firmware, I found out that it’s an Arduino library:

In file included from /home/scy/proj/cronologic/webusb/firmware/lib/vrekrer_scpi_parser/src/Vrekrer_scpi_parser.cpp:1:0:
/home/scy/proj/cronologic/webusb/firmware/lib/vrekrer_scpi_parser/src/Vrekrer_scpi_parser.h:30:21: fatal error: Arduino.h: No such file or directory
 #include "Arduino.h"
                     ^
compilation terminated.

There is no official Arduino support for the Pico boards (yet), only a third-party project.

We have three options now:

• Switch from the official C(++) SDK to Arduino to use the SCPI library
  • I’m not sure how stable the Arduino port is and what kinds of quirks and differences from the official SDK we’d have to expect.
  • Also, the Vrekrer SCPI library hasn’t been touched since half a year now anyway, maybe it won’t be developed further?
  • Additionally, it doesn’t support any parsing of values or units (bascially, it only does command splitting), we’d have to do that ourselves, too.
• Try another library
• Implement the parsing ourself

I’ll try out another SCPI parser library first and report back.

[scy]

I’ve managed to include the j123b567 library I was talking about in the previous comment in c943d9b21bd805bf250b0565a5697f9fa0f403dd and make it work with the Pico’s CMake-based SDK. Next step will be to actually implement some C code to parse the SCPI and respond.