Ginkgo USB-CAN Interface Part 2
The lack of documentation on this thing is obnoxious. Tenacity might be the only thing to get me through this. If you haven't seen my previous post (if you care), I am trying to write some software to use the Ginkgo USB-CAN interface on my 2007 Jeep Grand Cherokee. The Ginkgo (I am going to shorten it to this, since it should be pretty obvious what I am talking about) has a PDF associated with it on the Viewtool website which details the API's, though it does a confusing job of it. I should also add that there is some significant importance to knowing the baud rate of your CAN bus, and this is what had me stuck for a long time. There are some places on the internet, most specifically the work done by Chad Gibbons, that mention the 2013 Jeep CAN bus in his runs at 125 Kbps. I made a bad assumption that my 2007 would have had the same baud rate.
After referring to a Chilton's Manual on my particular model, I discovered that my CAN bus runs at 83.33 Kbps. This is great, except that the closest preset to this in the Ginkgo USB-CAN Extend software available on the Viewtool site is 80 Kbps. That is a pretty significant difference. I received some data, but it was more intermittent than I knew I should be getting. Oddly enough, the data was consistent when I received it. It was obvious that it wasn't correct, but this certainly got me farther than I had gotten before, and that was refreshing.
Something that should have seemed a little obvious was the menu entry in the bit rate settings that were written in Chinese. When this menu opened, I was able to input custom values for BS1, BS2, SJW, and BRP. I have not searched for the meanings of these, but the manual gives a few tables to help you decide, including examples for those common rates it has listed in the menu. That was not how I proceeded, mostly because I can be a little impatient. My solution was to plug in some values until I found what it was that I wanted, and the software instantly calculates for you. I found that most helpful. Here are the settings if you have an 83.33 Kbps CAN bus:
Data started pouring in when I set these values. What the data means is quite another problem to solve, but I saved the data to some CSV files for analyzing, and I should be able to refer to the Chilton's manual for some info. At least there has been some progress.
After referring to a Chilton's Manual on my particular model, I discovered that my CAN bus runs at 83.33 Kbps. This is great, except that the closest preset to this in the Ginkgo USB-CAN Extend software available on the Viewtool site is 80 Kbps. That is a pretty significant difference. I received some data, but it was more intermittent than I knew I should be getting. Oddly enough, the data was consistent when I received it. It was obvious that it wasn't correct, but this certainly got me farther than I had gotten before, and that was refreshing.
Something that should have seemed a little obvious was the menu entry in the bit rate settings that were written in Chinese. When this menu opened, I was able to input custom values for BS1, BS2, SJW, and BRP. I have not searched for the meanings of these, but the manual gives a few tables to help you decide, including examples for those common rates it has listed in the menu. That was not how I proceeded, mostly because I can be a little impatient. My solution was to plug in some values until I found what it was that I wanted, and the software instantly calculates for you. I found that most helpful. Here are the settings if you have an 83.33 Kbps CAN bus:
Code:
BS1 = 4 BS2 = 1 SJW = 1 BRP = 72
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