Building Jaguar A3 board Serial #1

[DeuceEFI]

This thread is the build diary for Jaguar A3 board Serial #1.

[DeuceEFI]

To bring you up to date with the build I will start with the modifications that I had to make after the initial electrical check with my DMM...

I found that both pads of R12 on the Through Hole side were connected to the ground plane and one pad of C1 that wasn't supposed to be connected to the ground plane on the Through Hole side. So I used my handy-dandy knife and cut the copper from around these pads and have edited the KiCAD PCB file so that others won't make the same mistake. This correction has been committed/pushed to my github repository.

The footprint for J2 is incorrect for the connection to GND, it was routed to the ID pin of the USB-B-mini connector and needs to be routed to the correct GND pin. This requires that one trace be cut and a jumper wire ran from the pin #4 connection point on the J1 connector to the GND pin on the J2 connector. I will test the USB-B-mini connector on the Serial #2 board build and make the appropriate change to my KiCAD footprint.

[DeuceEFI]

I have also determined from testing various crystal load capacitors (C10 and C11) that 22pF capacitors are required for the crystal that I have specified in my BOM. I have tried 12pF, 18pF and 20pF load capacitors as suggested by another contributor but found the crystal would not oscillate using those capacitor values.

[edit] 05/15/2012 4:50pm EDT
Actually the above information is WRONG, I had issues with the USB ground not being connected to the MCU ground which caused an issue with the USB comms and another issue with needing the PNP modification which was preventing the MCU from working without the USB plugged in. Since I have corrected these two issues, I have verified that the 20pF and 22pF crystal load capacitors do in fact work. The crystal manufacturer that I have chosen specifies a 20pF load capacitor for this crystal, but feel free to test other values, I have a pair of 18pF capacitors and may try those on a future build (ie: Jaguar #2) to see if they work as well.[/edit]

Also determined that the load resistor (R62) that connects between the crystal leads needs to be a 1M Ohm resistor (this resistor is NOT optional).

The optocoupler (U8 and U9) circuits have NOT been tested and may change to another device that Fred has found, here is a link to Fred's post in the Ravage project: viewtopic.php?f=58&t=1597&start=10

[DeuceEFI]

Ok, now for the actual build:

I will spare you the actual steps, which can be found in the Jaguar Assembly Manual. Pictures will be updated soon in the manual to the actual photos I took during assembly of the first board.

Started the build by installing all of the surface mount IC's on the SMD side of the board using solder paste and my DIY reflow soldering oven (plans can be found in my github repository for the reflow oven).

I have built and tested both power supply circuits and they work as designed.

I have added the components for the MCU and for the USB communications circuits without the optocouplers.

I have added the Check Engine Light (CEL) circuit components (R7 and D1).

I have flashed the MCU with the Serial Monitor program found in the FreeEMS-vanilla libs directory using my DIY TBDML (plans for this can be found in my github repository as well) and the Freescale Special Edition CodeWarrior (actually only installed CodeWarrior to use the HiWave.exe Debugger) to flash the Serial Monitor using the Windows version.

I have been able to upload the FreeEMS-vanilla firmware with the MegaTunix Firmware Loader and verified that MegaTunix can communicate with the MCU.

I have verified that the CEL (Yellow LED) blinks at 0.5 Hz while the MCU is running the FreeEMS firmware.

[DeuceEFI]

Also determined that the load resistor (R62) that connects between the crystal leads needs to be a 1M Ohm resistor (this resistor is NOT optional).

This statement was found to be incorrect, it is NOT necessary (hey that is what prototype testing is all about).
I will leave it in the schematic in case someone sources a crystal that needs a load resistor that way they will have a set of SMD pads to solder it to.

[DeuceEFI]

I have completed the assembly of my Jaguar A3 board Serial #1 per the Jaguar Assembly Manual found in my github.com repository, which will be updated with step by step photos later on today.

Attached to this post is a photo of the Through Hole side of the board.

[DeuceEFI]

Higher resolution of the same image from before...

[DeuceEFI]

Other side (SMD side) of the Jaguar A3 board.

[DeuceEFI]

Picture showing size comparison of a Jaguar A3 in the smallest case sitting on top of a MSpoo

[Fred]

Very cool! :-)