Possible solutions
Power-cycle your device and try to perform a reset
This way you will pinpoint the issue either with:
- Establishing a debug session (if reset fails as well)
- FLASH programming (if reset works, but download fails)
Verify Hardware and CPU Options configuration
An incorrect CPU selection, Reset selection, or debug clock may prevent you from establishing a debug session:
- Check CPU Device selection via Debug | Configure Session | SoCs
- Change Reset method from Regular to Stop
- Adjust JTAG Scan speed via Hardware | CPU Options | JTAG
- Check debug voltage levels and, instead of Vref, specify a fixed voltage in Hardware | CPU Options | Hardware. Error JTAGC ID: 0xFFFFFFFF OnCE ID: 0xFFFFFFFF BYPASS: 0x7FFFFFFF means that there is no response from the chip.
Make sure you are using SFR database that matches the winIDEA version you are running
SFR database holds various information, including how winIDEA should connect to the MCU. This information may be winIDEA version dependent, which is why matching SFR database should always be used.
More resources in winIDEA Help