I used the battery for power, only connecting SWD pins and ground. I see no reason it would not work with externally supplied power. For me it was more of a hassle, since you need to supply 5V though USB. It is just easier to keep the battery attached.
Alex, sorry, need to come back to this. So according to your github description I also need to also supply external 3.3V power to the programmer, correct?
I think you mentioned the existing chip cannot be programmed but can it be read? Before I replaced the chip I wanted to be sure my programming interface connections work so I tried connecting my Jlink as follows:
- SW to their respective pins on the scope board via USB connector
- GND to GND of the programmer
- Scope Battery connected to the scope board
- power up with F2 pressed to stop the ADC acq (LCD is off as you said)
- tried to connect to target - it wasn't successful.
Should I assume that connection is not possible if the chip is locked. If not what else am I missing. I know above connections are correct. But if the connections are correct perhaps I am missing the 3.3V external source to the programmer? Although it suggests Reset is high:
(Also, this particular JLINK programmer is actually supplying 3.3V on the voltage pin instead of expecting it - like with the original JLink - which is handy when programming as it does not require the target to be powered when connected)
Connecting ...
- Connecting via USB to J-Link device 0
- J-Link firmware: J-Link ARM V8 compiled Nov 28 2014 13:44:46
- Device "GD32F407VE" selected.
- Target interface speed: 4000 kHz (Fixed)
- VTarget = 3.261V
- RESET (pin 15) high, but should be low. Please check target hardware.
- RESET (pin 15) high, but should be low. Please check target hardware.
- RESET (pin 15) high, but should be low. Please check target hardware.
- RESET (pin 15) high, but should be low. Please check target hardware.
- RESET (pin 15) high, but should be low. Please check target hardware.
- RESET (pin 15) high, but should be low. Please check target hardware.
- RESET (pin 15) high, but should be low. Please check target hardware.
- RESET (pin 15) high, but should be low. Please check target hardware.
- ERROR: Failed to connect.
Could not establish a connection to target.
Many thanks,
Nick-