Flashing firmware onto NXP QN9020 via SEGGER J-Link

Question

Here I am attempting to flash the firmware using SEGGER J-Flash Lite.

Below is the ouput when attempting to connect via the SEGGER J-Link Commander.

JLinkExe 
SEGGER J-Link Commander V6.46j (Compiled Jul 12 2019 17:31:38)
DLL version V6.46j, compiled Jul 12 2019 17:31:27

Connecting to J-Link via USB...O.K.
Firmware: J-Link EDU Mini V1 compiled Jul 10 2019 16:32:48
Hardware version: V1.00
S/N: 801010920
License(s): FlashBP, GDB
VTref=0.000V


Type "connect" to establish a target connection, '?' for help
J-Link>connect
Please specify device / core. <Default>: QN9020
Type '?' for selection dialog
Device>
Please specify target interface:
  J) JTAG (Default)
  S) SWD
  T) cJTAG
TIF>
Device position in JTAG chain (IRPre,DRPre) <Default>: -1,-1 => Auto-detect
JTAGConf>
Specify target interface speed [kHz]. <Default>: 4000 kHz
Speed>
Device "QN9020" selected.


Connecting to target via JTAG
Cannot connect to target.
J-Link>connect
Device "QN9020" selected.


Connecting to target via JTAG
Could not measure total IR len. TDO is constant high.
Could not measure total IR len. TDO is constant high.
Could not measure total IR len. TDO is constant high.
Could not measure total IR len. TDO is constant high.
Cannot connect to target.

Connecting to target via JTAG
TotalIRLen = ?, IRPrint = 0x..000000000000000000000000
TotalIRLen = ?, IRPrint = 0x..000000000000000000000000
TotalIRLen = ?, IRPrint = 0x..000000000000000000000000
TotalIRLen = ?, IRPrint = 0x..000000000000000000000000
Cannot connect to target.

See also:

Freescale Kinetis KE - writing to flash

Is this a custom board? Can you post the schematic of the JTAG circuit? — Ron Beyer, Jul 24 '19 at 00:15

score 1 · Accepted Answer · answered Jul 24 '19 at 07:16

Your debugger is not properly connected. Telltale sign:

VTref=0.000V

Modern debuggers usually allow a wide target voltage range. Their level shifters will be set to the target voltage VTref.

But that also means there will be no output if VTref is zero volts.

Note: The above J-Link EDU Mini does not have level shifters, and is thus unsafe to use for any other target voltage than about 3.3 Volts. But it can still measure VTref, and needs this pin properly connected.

Flashing firmware onto NXP QN9020 via SEGGER J-Link

1 Answers1