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
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.
Would you mind telling me that the transistor is NPN or PNP or the model number? Thanks ^^
It's a BC850C (NPN)