CYW43907, jtag failure, unexpected voltage

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cedric_roomz
Level 4
Level 4
50 replies posted 50 sign-ins 25 replies posted

Hi,

 

I am able to write to a dev kit using a segger jlink, however when trying to program our custom hardware (which is very similar to the dev kit) it reads successfully the id 0x5BA00477 but quickly fails afterwards.

 

See output:

 

 

SEGGER J-Link Commander V7.63b (Compiled Mar  1 2022 16:42:47)
DLL version V7.63b, compiled Mar  1 2022 16:41:28

Connecting to J-Link via USB...O.K.
Firmware: J-Link V11 compiled Dec  9 2021 14:14:49
Hardware version: V11.00
S/N: 821008088
License(s): GDB
USB speed mode: High speed (480 MBit/s)
VTref=3.180V
Device "CYW43907" selected.

Connecting to target via JTAG
TotalIRLen = 4, IRPrint = 0x01
JTAG chain detection found 1 devices:
#0 Id: 0x5BA00477, IRLen: 04, CoreSight JTAG-DP
Identified core does not match configuration. (Found: None, Configured: Cortex-R4)
TotalIRLen = 4, IRPrint = 0x01
JTAG chain detection found 1 devices:
#0 Id: 0x5BA00477, IRLen: 04, CoreSight JTAG-DP

****** Error: Could not power up debug port: Control/Status register reads 00000F02
TotalIRLen = 4, IRPrint = 0x01
JTAG chain detection found 1 devices:
#0 Id: 0x5BA00477, IRLen: 04, CoreSight JTAG-DP
TotalIRLen = 4, IRPrint = 0x01
JTAG chain detection found 1 devices:
#0 Id: 0x5BA00477, IRLen: 04, CoreSight JTAG-DP
Cannot connect to target.

 

 

When looking at JTAG signals, we can see that the voltages are unexpected:

TDI/TMS: ~2.4V

TCK: ~2.5V

TDO/VTref: 3.3V

 

According to segger: 

The J-Link has 100 Ohm serial resistors at TDI/TMS and 68 Ohm at TCK. 

The voltage drop at TDI/TMS is 0.9V with 9mA load current

The voltage drop at TCK is 0.7V with 9mA load current

 

According to CYW43907 doc:

GPIO have programmable 2 mA to 16 mA drive strength. Default is 10 mA

 

Are the GPIOs set as output to GND with an empty flash?

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1 Solution
cedric_roomz
Level 4
Level 4
50 replies posted 50 sign-ins 25 replies posted

You can close this, it was a wiring mistake on the jlink (nTRST connected to ground)

View solution in original post

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1 Reply
cedric_roomz
Level 4
Level 4
50 replies posted 50 sign-ins 25 replies posted

You can close this, it was a wiring mistake on the jlink (nTRST connected to ground)

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