Hi, I have just bought ST uPSD33xx series development kit (DK3300-ELCD, uPSD3334D). In the kit, a keil uLINK USB-JTAG is included. When I use uLINK to debug , uVision shows the following error message : "JTAG Communication Failure" "JTAG Communication Failure" "JTAG Communication Failure" "JTAG Communication Failure" "JTAG Communication Failure" "*** error 122: AGDI: memory read failed (D:0x80)" I can program the development kit using uLINK (Must disconnect the uLINK after programming, otherwise, it will not work), but cannot enter debug mode. I observe that pin 8 in the J-TAG port, which is connected to the reset pin of the MCU, is always low. While I use another JTAG device (Raisonance RLINK-ST USB-JTAG Adapter, which work perfectly), the pin 8 is low only during program, when idle or debugging, pin 8 is high. So, may be this the reason why uLINK doesn't work? Does it mean that Keil uLINK is broken? Thank. Best regard. John
It's a BC850C (NPN)
Would you mind telling me that the transistor is NPN or PNP or the model number? Thanks ^^
According to your description, the ULINK might be broken. Pin 8 (Reset) is a open collector output with a 10K pull-up resistor. It is active low when the device is programmed/verified but must go high after that to start the application. Please open ULINK (screw at the backside) and check if the jumper is set to VCC=3.3. Then check the Reset voltage on pin 8 (pin 3, 10 and 12 is ground) when ULINK is only connected to the USB bus and not to your target system. You should see a voltage of 3.3 volts. If not, the transistor T1 might be broken or shortcut. ULINK needs to be replaced in this case.
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