Glasgow Embedded / Glasgow - History

firmware,software: add LED test mode (-67 bytes XRAM).

firmware: {bool→__bit} pending_setup (+92 bytes XRAM).

cli,device: split factory flashing off into its own flow.

Before this commit, some aspects of factory flashing (device
enumeration and initial loading of firmware) were handled in
the production flow. However, this interacted poorly with the device
recovery flow, since uploading a production firmware causes
the device to re-enumerate.
* Re-enumeration is not very reliable, especially on Windows. (#252)
* If more than one device is connected, re-enumeration could cause
the wrong one to be destructively reflashed, since USB has no
geographical addressing.
In addition, behavior related to `--force` depended on the device
EEPROM state, which is not appropriate to either factory flashing
or the recovery flows.

This commit solves these issues by separating (and simplifying)
the production and the factory flashing flows.
* The production flow only opens VID_QIHW:PID_GLASGOW devices
(factory flashed) and loads only the production firmware.
* The factory flashing flow opens VID_CYPRESS:PID_FX2 devices with
no options, and VID_QIHW:PID_GLASGOW devices with `--reinitialize`.
* The factory flashing flow loads the Cypress bootloader firmware,
regardless of VID:PID. It ignores the EEPROM contents and flashes
the configured revision and serial, as well as the built-in
firmware, and asks the operator to power cycle the device.

The notable differences are:
* The factory flashing flow is incomparably more reliable.
* The factory flashing flow is flashing a firmware in addition to
the configuration block, halving the amount of programming steps.
* The factory flashing flow no longer attempts to prevent you from
flashing an already factory flashed device. This might seem bad at
first glance, but:
- It was added, IIRC, to handle potential re-enumeration bugs,
which are no longer present.
- It actively got in the way most of the time.
- It's not *that* destructive--you just lose your serial, and
even that only if you did not have it on a sticker or written
down somewhere. (If you care about the serial it is probably
because you have it in a script somewhere, so the problem of
backing it up solves itself.)

Fixes #252.

software: use PDM to manage dependencies on CI.

At the moment (since commit 36769e73) synthesis tests are not running
on CI because a request to install nonexistent optional dependency
group is silently ignored by pip.

Pip is not really suited for this workflow, so use PDM instead, and
also set up the `pdm run test` alias since the test runner is liable
to change in the future.

applet: adjust `synthesis_test()` to use target.toolchain.

Add CODEOWNERS.

This is a trial run of the functionality more than anything.

target: cache bitstreams.

This is a major usability improvement for two use cases:
* routine and recommended use of the reset button on revC2+, which
is otherwise excruciatingly slow;
* frequent switching between multiple specific applet configurations,
useful as a workaround for the lack of multiple applet support.

This commit should make most uses of `run --prebuilt` obsolete.

Fixes #43 (again).