Serial port communication

2011 7 31
3 个回答
回答已采纳
26 次查看（30 天）

0 个投票

I have an On-Board Diagnostics (OBDII) tool that I am trying to read the values from. This tool helps me trouble codes on a car's ECU. I can use hyperterminal to read the values through the USB. When I open the terminal with COM1, baud rate of 9600 and type in 03, it returns me some value.
How do I do the same in MATLAB? Is this it or do I need to do more?
s = serial('COM1'); fopen(s) fprintf(s,'03') out = fscanf(s)
Please suggest.

请先登录，再回答此问题。

 采纳的回答

Krishna Gummadi
Krishna Gummadi 2011-8-2

0 个投票

I had to add this before fscanf to work:
fprintf(s,'%s','13'); %CR

1 个评论
显示 -1更早的评论 隐藏 -1更早的评论

Walter Roberson
Walter Roberson 2011-8-2
'13' would not send a CR, but 13 not in quotes would. That would be the same, though, as coding \r in the format like I suggested.

请先登录，再进行评论。

更多回答（2 个）

Walter Roberson
Walter Roberson 2011-7-31

0 个投票

What terminator does the remote system need? fprintf(s,'03') is defined as fprintf(s,'%s\n','03') which sends 03 followed by whatever terminator is configured for the port. If that terminator does not match what the remote system is expecting, you could have difficulty.
Krishna Gummadi
Krishna Gummadi 2011-7-31

0 个投票

The document indicates this:
"All messages to the OBD Prompt must be terminated with a carriage return character (hex ‘0D’) before it will be acted upon. If a command has been started but not terminated by a ‘0D’ it will be aborted after 20 seconds of inactivity"
So, should I say fprintf(s,'030D') instead?

1 个评论
显示 -1更早的评论 隐藏 -1更早的评论

Walter Roberson
Walter Roberson 2011-7-31
You could set the terminator to carriage return, or you could use
fprintf(s,'%s\r', '03')

请先登录，再进行评论。

类别

在 帮助中心 和 File Exchange 中查找有关 MATLAB Support Packages 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by