I'm having a little difficulties using both STM32 and ICE40 simultaneously

[afiskon]

Hello everyone,

I would like to configure ICE40 and then program STM32 MCU using STLink v2. The MCU firmware blinks with the blue LED on PA15 / PMOD[52] which is marked as input on ICE40 side.

The problem is that when I program STM32:

st-flash --reset write build/$(TARGET).bin 0x8000000

... unless I connect RST pin of STLink with RST pin of BlackIce II the new firmware doesn't start. And if I do connect these pins ICE40 restarts as well and doesn't has the configuration I need.

I thought maybe I can restart the MCU over SWD using OpenOCD, but for some reason this time OpenOCD has difficulties connecting to the MCU. It hangs like this:

$ openocd -f /usr/share/openocd/scripts/interface/stlink-v2.cfg -f /usr/share/openocd/scripts/target/stm32l4x.cfg

Open On-Chip Debugger 0.10.0
Licensed under GNU GPL v2
For bug reports, read
	http://openocd.org/doc/doxygen/bugs.html
Info : auto-selecting first available session transport "hla_swd". To override use 'transport select <transport>'.
Info : The selected transport took over low-level target control. The results might differ compared to plain JTAG/SWD
adapter speed: 500 kHz
adapter_nsrst_delay: 100
none separate
Info : Unable to match requested speed 500 kHz, using 480 kHz
Info : Unable to match requested speed 500 kHz, using 480 kHz
Info : clock speed 480 kHz
Info : STLINK v2 JTAG v29 API v2 SWIM v7 VID 0x0483 PID 0x3748
Info : using stlink api v2
Info : Target voltage: 3.236436
Info : stm32l4x.cpu: hardware has 6 breakpoints, 4 watchpoints

Naturally I could just use a separate STM32 development board but now I'm curious Am I doing something wrong? What is a recommended way to do what I'm trying to do? Can I configure ICE40 permanently?

[lawrie]

Usually the program that runs on the STM32 has some way to configure the FPGA. iceboot looks for a bitstream at 0x0801F000 or reads one from the USB connection. Programs such as the BBC Micro emulation contain a version of iceboot and their bitstream at address 0x0801F000, so that they configure their bitstream whenever they are booted. The Arduino examples have the bitstream in a header file. Another program I have used reads the bitstream from the SD card. If your STM32 program does not have some way of configuring the bitstream it needs in the Ice40, you are going to have difficulties.

(Unless you configure the Ice40 from a Raspberry Pi using the SPI pins in the Rpi header, which I have done, but is probably not a solution for most scenarios).

[Folknology]

The design is based around the STM32 programming and managing the Ice40, thus when programming the STM32 one should also have that program include bitloading the Ice40, that means STM32 boot first then it brings up the Ice40 with a bitfile (normally in flash). You could start developing you program from the iceboot to make this process easier perhaps.

There is one other possibility if the mux is set correctly (and the STM32 GPIOs do not interfere) the Ice40 can be programmed from the outside using a RaspberyPi for instance, however this is more complex.

[afiskon]

OK, I just generated .h file with the configuration using xxd utility and imported iceboot logic into my project. It was quite easy. Thanks everyone!