Help with Sabvoton and USB ($20 PayPal reward!)

[alec]

$20 of beer money via PayPal or Square Cash to whomever helps me solve this problem that has been plaguing me for the past week. I am also willing to donate it to a charity of your choosing.

I finally got my Sabvoton MQCON 960150 playing nice with my CA3-DP and Cromotor V3. It took hours, days (actually, 50 hours, I counted) to get it working. The biggest slap to the face, it’s in reverse with an abysmal current limit. Unrideable. Now I just have one more, rather blazing hurdle to hop over –

I cannot for the life of me get my PC to connect to this Sabvoton. The TX light just blinks away, seemingly mocking my futile efforts.

Here’s what I’ve tried:

1) Purchased an HC-05 module (what Sabvoton uses as their “Bluetooth dongle”). Chopped female USB out from controller to reveal four wires (5V, GND, TX, RX). I set the baudrate to [strike]19600[/strike] 19200 and hooked it up to the TX and RX. No response via my Bluetooth COM. TX light just blinks away.

2) Purchased a USB to Serial TTL cable. In same manner, directly hooked it up to Sabvoton’s exposed serial wires. No response. Same result.

Observations, respectively:

1) I noticed that the GND wire for the serial isn’t actually grounded. It shows up as 0L on my multimeter. So I took my bench power supply and powered/grounded 5V into the HC-05, bypassing the output of the Sabvoton minus the RX and TX. Now that I realize it, this may have been ineffective due to the fact serial uses the ground as a variable while transferring data.

2) I did not hook up the red 5V from the USB adapter as I did not want to blow up the Sabvoton’s internals. I was not able to observe anything over my serial monitor.

What the hell do I do?! Do I really have to order one of those cables from China with $20 shipping? Why can I simply not get this to work?

Relevant information, etc –
Windows 7 PC.
Tried using drivers included with controller but it was for an entirely different chip.
Tried different baudrates. Different COM ports.
Tried swapping RX/TX.

 

[Manny]

you can check the ground connection from the "USB" connector to the plug on the sabvoton side.

the ground connection connects to pin 1.
5 volt is on pin 2 .
USB white is on pin 7.
USB yellow is on pin 6

if there is a brake in the ground line, you can use any other ground wire. from the throttle connector for example.

the data uses 19200 baud rate. i think your 19600 is a typo.

hope this helps. Good luck

 

[alec]

you can check the ground connection from the "USB" connector to the plug on the sabvoton side.

the ground connection connects to pin 1.
5 volt is on pin 2 .
USB white is on pin 7.
USB yellow is on pin 6

if there is a brake in the ground line, you can use any other ground wire. from the throttle connector for example.

the data uses 19200 baud rate. i think your 19600 is a typo.

hope this helps. Good luck

Yes, that's a typo! I corrected it.

Pin 1, Pin 2, etc. are all referring to the "big" harness plug, correct? The one that has hot snot (glue) covering the connections?

Using any other ground wire would be rerouting the black gnd to the throttle connector at the harness connector level, correct? If the ground is broken, would it cause the serial connection to time out or otherwise be inoperable?

Thanks so much Manny. You've already done so much to help us Sabvoton troubleshooters.

 

[alec]

you can check the ground connection from the "USB" connector to the plug on the sabvoton side.

the ground connection connects to pin 1.
5 volt is on pin 2 .
USB white is on pin 7.
USB yellow is on pin 6

if there is a brake in the ground line, you can use any other ground wire. from the throttle connector for example.

the data uses 19200 baud rate. i think your 19600 is a typo.

hope this helps. Good luck

Pin 1, 2, 6 And 7 appears to be 11, 16, 17, 19 on my end.

Reference: https://goo.gl/images/e69v4j

What are these 1, 2, 6 and 7? Are you talking about internally or on the “big” (B[x]) plug?

 

[Manny]

i whas thinking about this type of sabvoton.

so lets try again.

check the connections between the "USB" and the connector going in the sabvoton.

if the ground is broken the serial com's will not work

 

[alec]

https://imgur.com/gallery/Kw3MZ

Here’s a look at what I’m dealing with.

I jumped the ground to the black throttle wire. That seemed to close the circuit up. Still no RX on the PC side.

Rx/Tx stick around 3v. Red is 5v.

Tried using the HC-05 module and also my USB to TTL. Tried setting baudrate to 19200 and a variety of others. Used odd pairity and then when that didn’t work, tried even, etc.

I have a suspicion that this is using a totally different kind of serial output. RS485?

If that’s the case, then an authentic programming cable won’t work either. I got totally screwed here.

Wish the original seller, Zombiess, would lend some advice. I’ve reached out and even tried contacting him via Facebook with his real life name; no response.

 

[Manny]

have you tried to flip the green and white wire?

if it is rs485 you will need a other converter.

can you open up the controller to check if there is a rs485 converter chip?

 

[alec]

have you tried to flip the green and white wire?

if it is rs485 you will need a other converter.

can you open up the controller to check if there is a rs485 converter chip?

http://ebike.nexun.pl/wp-content/uploads/2014/08/SSC.pdf

According to the spec sheet, it is indeed RS485. Pretty funny how they’d be willing to sell me a USB cable and Bluetooth dongle that are RS232. No wonder why this hasn’t worked for me.

I’ve got the proper converter coming in the mail tonight. I hope this works, I’ll keep ya updated.

I’m definitely writing an unofficial setup guide after this whole experience. No other controller deserves it more.

 

[alec]

Also, do you think the baudrate is still 19200 even though it’s RS485? Any way to test for output baudrate?

 

[Manny]

the baudrate will probably be the same. i think my controller has a empty spot on the PCB for a rs485 converter chip.

 

[alec]

the baudrate will probably be the same. i think my controller has a empty spot on the PCB for a rs485 converter chip.

Cool! I just got a KK 232->485 DB9 converter that should do the trick.

 

[amberwolf]

Rx/Tx stick around 3v. Red is 5v.

The 3v is not likely a true reading. What you're probably seeing is the meter trying to average the serial data pulses, which you could see with an oscilloscope, or if you have a Frequency Counter (Hz) measurement on your meter, it'll also indicate a pulse train rather than a DCV measurement. AC Volts may also show a voltage for a pulse train (where it wont' for a steady DC Voltage).

 

[alec]

Rx/Tx stick around 3v. Red is 5v.

The 3v is not likely a true reading. What you're probably seeing is the meter trying to average the serial data pulses, which you could see with an oscilloscope, or if you have a Frequency Counter (Hz) measurement on your meter, it'll also indicate a pulse train rather than a DCV measurement. AC Volts may also show a voltage for a pulse train (where it wont' for a steady DC Voltage).

You’re exactly correct! I hadn’t realized that during my initial testing.

 

[CluelessSabvoton]

I'm also offering a $$ bounty to this same issue. Was this resolved?

I'm desperate to get this thing going it won't talk with win 8.1 or 10.