Ultimate J-Link programming adaptor

[liteyear]

What would your ultimate programming adaptor look like?




I'm looking to design one and release it to the community to solve a common industry frustration. So far I have:

• Not cost $60+ for a bare bones connector board!
• Support at least a few common programming cables, so you need less adaptors.
• Right-angle IDC plug to plug straight into J-Link.
• 20-pin, 10-pin and 6-pin 0.1" IDC socket headers
• All configuration via 0.1" jumpers, instead of solder bridges
• Jumper to configure Target supply voltage: none, 5V, 3.3V
• Test points for everything
• Documentation rich silkscreen
• Additional header to connect a USB to serial adaptor, with jumpers to bridge it to some NC pins?

Maybe some nice to haves:

• LEDs for power and comms?
• Prototyping area for custom expansion?
• 0.05" header?
• Push button for reset?
• Jumpers to define own pin mapping?
• On board FDTI?

Thoughts?

[tellurium]

I own these from Ali:

https://www.aliexpress.com/item/1005001992920613.html
https://www.aliexpress.com/item/1005002058682164.html

Almost never used the 1st one, but often the 2nd one.

What I often needed is a serial converter, so your idea about the on board FDTI would make it quite attractive.

[dobsonr741]

Target supply voltage: better to sense target voltage with LVC2T45 than configure and dry by mistake. Target could be powered off, so sensing protects your target.

[darkspr1te]

A lot of the features you mention are provided by the Dangerous prototypes bus blaster , except "standard cable pins" side but it had reconfigurable pins via change to cpld, dual UART , voltage (none,3.3v,5v, user provided down to 1.2v) and it could emulate other jtag adapters  and swd as well. it's party trick is to be able to emulate two j-links , handy when you trying to fix a asus router with two jtag ports.
A real trick would to be a combo of the Bus pirate , that is emulate any 5<  wire protocol sans level converters (eg rs-232/485/CAN Bus/KKline) and provide hardware jtag , with upgradable front end we can also emulate a few flash/prom programmers (hardware required for 12v stuff can be community design)


I recently worked on a device where i had JTAG for two cpu's via the busblaster +bus pirate (needed 1.8v and BB second port does only 3.3v) and two uarts (used stm32 with zenier droppers) and 1 spi eeprom chip (used stm32 with flashrom code) , this was too many devices on my desk and a issue was bound to occur and the project failed, had this been one device i dont think i would have had the issue. But yeah, i had a cable come loose while checking things and it hit 5v into a 1.8v system and job over.


darkspr1te

[ejeffrey]

I've been using the jlink plus (not pro) for some years now, primarily with the nxp nee freescale kinetis MCUs and I have to say it's expensive but it works well. Flashing, debug, and I particularly like the segger RTT as a debug console instead of using a uart.   It's been good enough (and I've already got the device). 

[ajb]

I designed the simple purple PCB below ages ago (as evidenced by the dust and crud it's a accumulated  ). 99.9% of the time I just want a 10 pin SWD header in 50mil or 100mil pitch, so that's what it's got, plus a target power LED and a reset switch. I think I shared the design on osh park, along with similar ones I designed for the Atmel ICE and stlinkv2.

I did make a more complex adapter that includes a 3v3 regulator, and some dip switches to enable power to the target at 5V or 3v3, plus switches to route the J-Link UART rx/tx to pins 7 and 8 of the 10 pin headers, along with a 100mil header in the standard FTDI pin out. The idea was to have one adapter and one cable to the target for SWD and debug UART, but then I found out that the J-Link is limited to fairly low baud rates. I typically run debug UART as fast as I can, usually 250k, 1M, or 3M (which is the max for the FT232 et al -- though some of those parts go up to 10M). Plus I don't think I've ever actually used a J-Link to provide that power. So I gave up on that version and have been sticking with the simpler one plus a separate FT232 cable.





EDIT: Found the OSH Park project links:

JLink adapter: https://oshpark.com/shared_projects/oIF2gllI

ST-Linkv2 adapter: https://oshpark.com/shared_projects/765ksHTd

Atmel-ICE adapter: https://oshpark.com/shared_projects/JjUfnP7a

An integrated FTDI chip or something like that brings the problem of an additional USB connection. Maybe a vertical USB connector on the back of the PCB, so that the cable lays along the side of the Jlink could make that work?  I kinda like that, actually.

[liteyear]

I own these from Ali:

https://www.aliexpress.com/item/1005001992920613.html
https://www.aliexpress.com/item/1005002058682164.html

Oh that first one's nice, particularly with the cable kit. It strikes me though that I've never needed most of those pinouts, but have often needed 6-way IDC, which it is missing! I guess we all have our own version of "universal".

I designed the simple purple PCB below ages ago (as evidenced by the dust and crud it's a accumulated  ). 99.9% of the time I just want a 10 pin SWD header in 50mil or 100mil pitch, so that's what it's got, plus a target power LED and a reset switch. I think I shared the design on osh park, along with similar ones I designed for the Atmel ICE and stlinkv2.

Nice form factor! Reminds me of the Joulescope front-panel concept. Though I wonder if it compromises available real estate too much.

better to sense target voltage with LVC2T45

Oh good one! I'll look into it, but I would have thought the programmer would already do this? To be clear, I'm only considering an adaptor that plugs into an existing programmer.

A lot of the features you mention are provided by the Dangerous prototypes bus blaster

My killer feature is actually the physical sockets, and the active features are more a "may as well", so this is coming at it from the other direction which is interesting. Looking it up led me to this relevant attempt at adding a universal adaptor the BP!

Thanks everyone for the great ideas. I think it's becoming clear that scope creep is a core challenge! There's so many potential use cases, but throwing the net too wide will quickly compromise that key quality of "handiness".