Glasgow Embedded / Glasgow - History

applet.spi.flash_25c: add HOLD# pin, always high.

Flashes (usually?) don't have an internal pullup there, so
an explicit pin makes it easier to remember that, and use a straight
8-to-8 socket adapter, if we ever get any.

applet.spi.master: SS should always be driven.

This broke spi.flash-25c applet in mysterious ways.

applet.spi.flash_25c: use proper dummy byte count for RDP.

access.direct.multiplexer: fix FIFO flush write port forwarding.

This caused flush to be never asserted, and stuck FIFOs.

applet.spi.master: fix refactoring issue.

This broke dependent applets like applet.spi.flash_25c.

access: allow hinting reads for dramatically improved performance.

The `hint` argument to `read` chooses the size of the buffer
submitted to the OS. It should be set to the amount of data expected
to be recived, and using it correctly is essential to avoid
FIFO underflows and poor performance.

gateware.fx2: replace "non-streaming" FIFOs with "auto-flush" FIFOs.

The difference is that all FIFOs are now flush-capable, and
auto-flush FIFOs simply always assert flush. This means that applets
can flush on demand.

The manual-flush mode currently has an issue where if a flush is
asserted after all data is already transferred into the FX2 side
FIFO, the packet is not sent. Thus, it is not usable in general.

applet.jtag.pinout: also probe TRST# if pulldowns are detected.

There is no need to probe it if it has a pullup or is Hi-Z because
we get all those to high before probing other pins.

Also write out the arguments to the `jtag` applet. This isn't
entirely correct as it'll break with indirect access, but it's good
enough for now.