Can't connect via Bluetooth, module confirmed functional

tightwad · Post by **tightwad** » Sun Oct 13, 2013 12:57 am

I am trying to connect via Bluetooth. I have power linked from the MAP sensor and Receive from the third pin and transmit from the 4th pin (looking at the board, reading bottom row left to right). The software has a Runtime error when I connect the transmit wire...the error is:

"This application requested the Runtime to terminate it in an unusual way"

I tested the bluetooth module using TeraTerm (with transmit/received connected together). The test was successful (I was able to see the text as I typed it)

I tried Baudrate of 9600 and 38400, no difference.

I tried swapping the Transmit and Receive lines, no change.

Any suggestions?

Post by **brentp** » Tue Oct 15, 2013 10:54 pm

Hi,

Does the software work when connected with regular USB->Serial?

tightwad · Post by **tightwad** » Tue Oct 15, 2013 11:06 pm

brentp wrote:Hi,

Does the software work when connected with regular USB->Serial?

I don't yet have a USB-Serial cable (on order now). I will update when I try with the cable.

tightwad · Post by **tightwad** » Sat Oct 19, 2013 12:25 am

I borrowed a USB to Serial converter. It has an FTDI chip. I wired the RJ11 to the convertor...pin 1 is TXT, 2 is RCV and 3-4 are ground.

When trying to read the map I get alternating:

Timeout reading cylinder count
Timeout reading ignition configuration

Using a vacuum pump gives me no change to the MAP readings.

I am guessing I am still not successfully connecting, not sure of the next troubleshooting step.

Post by **brentp** » Sat Oct 19, 2013 5:21 am

Hello,

Can you identify if the megajolt basically functions? i.e. does it power up and control ignition advance on the engine? (verify using a timing light) - This is a first step to identify if the Megajolt firmware is alive and running.

Are you using a serial cable you built or the one purchasable with the unit?

tightwad · Post by **tightwad** » Mon Oct 21, 2013 2:18 am

brentp wrote:Hello,

Can you identify if the megajolt basically functions? i.e. does it power up and control ignition advance on the engine? (verify using a timing light) - This is a first step to identify if the Megajolt firmware is alive and running.

Are you using a serial cable you built or the one purchasable with the unit?

Brent,

I haven't yet tested the MegaJolt in the vehicle...it's going into a 2 stroke Wetbike (watercraft) and needs to be in the water to run for any extended period of time. My goal was to verify I could connect and then load a basic map (based around the stock timing action)

The Serial cable I am using is an Arduino adapter cable. For the adapter I used a 4 cable phone cable I clipped the ends off of and soldered on pins to plug into the serial board. I confirmed that the serial adapter is working in the computer but when I connect the MegaJolt I get the error stated previously.

The MegaJolt powers up (light turns green) when i connect 12V in from my battery pack.

Post by **brentp** » Mon Oct 21, 2013 2:50 am

Can you better describe / pic / link to the arduino adapter cable? the Megajolt needs RS232 level signaling- 3.3v or 5v logic level signals will not work.

tightwad · Post by **tightwad** » Wed Oct 23, 2013 1:57 am

brentp wrote:Can you better describe / pic / link to the arduino adapter cable? the Megajolt needs RS232 level signaling- 3.3v or 5v logic level signals will not work.

The original adapter I tried:
http://moderndevice.com/product/usb-bub-i/

I tried a second adapter. This is a direct USB to serial output:
http://www.ebay.com/itm/USB-To-RS232-TT ... OC:US:3160

Both are recognized by windows 7 and both give the same timeout errors. I verified that the pins match the diagram and that the wires all conduct as they should.

Can I get another board to try or are there more troubleshooting tests I can do on this board? It appears the issue is not with the adapters unless I just have terrible luck....3 adapters that all result in error. I have soldered in the Rev Limiter to fit in the case with the MegaJolt board as well.

tightwad · Post by **tightwad** » Wed Oct 23, 2013 2:19 am

According to the V4.0 Rev A diagram Chip U2 should have continuity from pin 13 and 14 to pin2 and 1 on the RJ11 jack. This is not the case, I get an open circuit.

tightwad · Post by **tightwad** » Sat Nov 02, 2013 10:18 pm

I connected my Serial Port adapter directly the to pins of the chip and I am able to read/write to the MegaJolt. Has anyone seen the traces not complete between the serial chip and the RJ11 jack? I don't really like that I have to hack it to make it work as it is supposed to.

Alex B · Post by **Alex B** » Sun Nov 24, 2013 5:21 pm

Make a scan of the circuit board and post it, maybe we see something is not how it should be.

Alex

Post by **brentp** » Fri May 16, 2014 3:38 pm

You may want to try this module; it should work out of the box using the standard Megajolt communications cable after it's been configured for 38400 baud.

http://ww1.microchip.com/downloads/en/D ... 240-DS.pdf