I am not sure that it is the FPGA that is the trouble. To me it sounds odd that you would first do a lot of FPGA work before you would show the splash screen.
Your device is bricked. The most likely reason in such case is that MCU waiting handshake acknowledgement from FPGA firmware. Since FPGA firmware is broken, it never send acknowledgement (or sends incompatible handshake response) and MCU waits for infinite. That's my point of view.
Also, the update program ITSELF fails telling "Failed or not responding" immediately. I assume the update is handled by the stm32, so to me it feels like that one is buggered.
Yes, update is handled by STM32, but you're needs to enter into bootloader mode and confirm enter into bootloader on device. Without bootloader update tool will show you "failed or not responding" error or something like that.
But since STM32 is waiting response from FPGA, it cannot complete initialization and you cannot enter into bootloader mode. So, broken FPGA update can brick your signal generator.
Your PC can see USB serial port because signal generator use USB-serial chip CH341. STM32 is not involved in such detection.
Try to run
ARB wave update tool without read/write option:
PSG9080_ARB COM1
where COM1 is a serial port of your PSG9080.
It requests device info from PSG9080. If it doesn't respond, then it's bricked.
The bricked device cannot be fixed with firmware update tool and requires direct firmware update through JTAG and EEPROM programmer. Unfortunately there is no RAW firmware files for PSG9080 in open access, so you cannot restore STM32 firmware.
I did get a new firmware file from our Chinese friends. This one contains an update ending in 56 78 so it should be an mcu update. But it cannot be placed due to the firmware upgrade issue.
The firmware link that you posted before:
http://68.168.132.244/PSG9080%20Firmware%20upgrade.ziphas the file name
0-256okh.bin
and it has
12 34 bytes at the end of file, this is ID for FPGA update type.
The file MD5: 8BFA094E33A656F1C2B75C206638BF7E
There is no MCU update for
Juntek PSG9080 device. At least I never seen it on internet.
The only MCU update for PSG9080 that I know is MCU update for
Joy-IT PSG9080. But it is not compatible with
Juntek PSG9080.
It looks that you run MCU update with a wrong firmware. Can you please share firmware file which you used for update?
If this is the case, then your device is now has Joy-IT PSG9080 firmware for MCU and this is the reson why it cannot handshake with a Juntek FPGA firmware.
There is no way to restore firmware for MCU, because there is no firmware in open access and I'm afraid manufacturer will reject your request to share it, because they scary for clones from other manufacturers. But in such case you can try to write FPGA firmware from a Joy-IT PSG9080 it can help to survive device under Joy-IT brand.
Warning: In any way, backup the content of flash IC before any expreiment or manipulation to keep the way to restore it in the previous state.There is an empty socket for a pin header on the display board; any idea whether that would be a jtag thing? Or is there any other way I could get that stm32 into boot loader mode or something similar?
Yes, this is JTAG for STM32 I tested it with DMM and the pins of this pin header are going to a JTAG pins of STM32. But I think that STM32 is protected after firmware upload on the factory. So there is no way to download firmware from the chip and only manufacturer have such file.
I tried to connect to STM32 through JTAG but it didn't respond, so this is a sign that the controller is protected from firmware download. I'm not sure for 100%, because I just leaned pins to a JTAG header for a test, so may be it fails to connect due to a bad contact. But I don't see the reason why manufacturer can leave firmware open for download, because it will allows to clone device and Chinese guys obsessed with protecting against it.