Install the required linux tools:
$ sudo apt install pkg-config libftdi1-2 libusb-1.0-4
Compile the iceprog program by doing
cd sw/vendor/yosyshq_icestorm/iceprog
make
Plug a micro-USB into the EPFL programmer, and connect the EPFL programmer to the Pynq-z2 FPGA PMODs.
We use the the FT4232H which has Vendor ID 0x0403 and Product ID 0x6011.
On your Linux shell, execute lsusb, you should see something like:
Bus 001 Device 006: ID 0403:6011 Future Technology Devices International, Ltd FT4232H Quad HS USB-UART/FIFO IC
and by executing dmesg --time-format iso | grep FTDI you should see something like:
2022-07-14T11:32:47,136453+02:00 usb 1-1.6: FTDI USB Serial Device converter now attached to ttyUSB4
2022-07-14T11:32:47,136543+02:00 ftdi_sio 1-1.6:1.3: FTDI USB Serial Device converter detected
2022-07-14T11:32:47,136878+02:00 usb 1-1.6: FTDI USB Serial Device converter now attached to ttyUSB5
Now do this, use B for the SPI, -t to read the FLASH ID
./iceprog -d i:0x0403:0x6011 -I B -t
You can also do this by running the following command
make flash-readid
The output should be:
init..
cdone: high
reset..
cdone: high
flash ID: 0xEF 0x70 0x18 0x00
cdone: high
Bye.
If you get:
init..
Can't find iCE FTDI USB device (device string i:0x0403:0x6011).
ABORT.
create a file called 61-ftdi4.rules (or whatever) in the folder /etc/udev/rules.d/ (you need sudo permits).
Write the following text in the created file to describe the attributes of the FT4232H chip:
# ftdi4
ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6011", MODE="666", GROUP="plugdev"
You may also need to run sudo usermod -a -G plugdev yourusername and restart the utility with sudo udevadm control --reload.
You may want to unplug and plug back the USB cable and repeat the iceprog command.
Reset the bitstream of the FPGA, and build it as
make vivado-fpga FPGA_BOARD=pynq-z2
You need to reset the bitstream to avoid conflicts when programming the FLASH from the FTDI chip.
Generate the C program you want to execute as described in the ExecuteFromFlash,
then program the FLASH as:
./iceprog -d i:0x0403:0x6011 -I B ../../../build/main.hex
You can also program the FLASH by running:
make flash-prog MAINFILE=<main_file_name_of_the_project_that WAS_built WITHOUT EXTENSION>
You can read the content of the FLASH as:
./iceprog -d i:0x0403:0x6011 -I B -r flash_content.txt
xxd flash_content.txt > flash_content.dump.txt
Now program the FPGA with the x-heep bitstream:
cd build/openhwgroup.org_systems_core-v-mini-mcu_0/pynq-z2-vivado
Remember to set the boot_sel_i and execute_from_flash_i switches to 1.
Reset the logic (so the x-heep reset and not the bitstream reset) and enjoy.
Additional note: To use the flash directly from X-HEEP, you first need to execute from the PC any iceprog command targeting the Flash. On the exit of any iceprog program, the FTDI pins will be set to high impedance. If this is not performed, the pins from the FTDI won't be on high impedance and the SPI signals cannot be driven from X-HEEP (or any other device).