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ELM329P 参数 Datasheet PDF下载

ELM329P图片预览
型号: ELM329P
PDF下载: 下载PDF文件 查看货源
内容描述: CAN解释 [CAN Interpreter]
分类和应用:
文件页数/大小: 76 页 / 353 K
品牌: ELM [ ELM ELECTRONICS ]
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ELM329  
Using CAN Extended Addresses  
Some vehicles with CAN interfaces use a data  
format that is slightly different from what we have  
described so far. The data packets look very similar,  
except that the first byte is used for the receiver’s (ie  
target’s) address. The remaining seven bytes are used  
as described previously.  
We refer to this type of addressing as ‘CAN  
Extended Addressing’, and provide support for it with  
the AT CEA commands. Perhaps an example would  
better describe how to use them.  
>AT SH 7B0  
OK  
Notice that there was a flow control message that  
was sent in this group, but it’s not quite the same as  
the one for OBD systems. For this reason, you’ll need  
to define your own flow control with the following three  
statements (we won’t show the OK’s any more, to  
save space):  
>AT FC SH 7B0  
Here is a portion of a data transfer that was taken  
from a vehicle. For the moment, ignore the first data  
bytes on each line and only look at the remaining data  
bytes (that are outlined in grey):  
>AT FC SD 04 30 FF 00  
>AT FC SM1  
The final setup statement that you will need is to  
tell the ELM329 to send to CAN Extended Address 04:  
7B0 04 02 10 81 00 00 00 00  
7C0 F1 02 50 81 00 00 00 00  
7B0 04 02 21 A2 00 00 00 00  
7C0 F1 10 16 61 A2 01 02 05  
7B0 04 30 FF 00 00 00 00 00  
7C0 F1 20 DF 01 00 04 09 01  
7C0 F1 21 02 05 DF 01 00 04  
7C0 F1 22 09 01 00 04 01 00  
>AT CEA 04  
Now everything is configured. Next, tell the IC to  
use this protocol, and to bypass any initiation (as it is  
not standard OBD, and would likely fail):  
>AT SP B  
>AT BI  
If you are familiar with the ISO 15765 data format,  
you will be able to recognize that the data bytes shown  
inside the box seem to conform to the standard. The  
rows that begin with 02 are Single Frames, the one  
that starts with 10 is a First Frame, while the one with  
30 is a Flow Control, and the others are Consecutive  
Frames.  
The remaining bytes, shown outside the box, are  
the standard 11 bit CAN ID, and an extra address  
byte. The lines with F1 for the extra address are  
directed to the scan tool (all scan tools generally use  
F1 as the default address), and the other lines are  
being sent to the vehicle’s module (at address 04).  
The ELM329 is able to handle these types of  
messages, but does require some setup. For example,  
if the messages use 11 bit IDs with ISO 15765  
formatting, and the baud rate is 50 kbps, then the PB  
command to configure protocol B is:  
That’s all. To exactly reproduce the flow of data  
shown, you only need to send the relevant data bytes  
and the ELM329 will add the rest:  
>10 81  
50 81  
>21 A2  
016  
0: 61 A2 01 02 05  
0: DF 01 00 04 09 01  
1: 02 05 DF 01 00 04  
2: 09 01 00 04 01 00  
Notice that for some reason, this vehicle has sent  
two segment 0’s, but that just means that it doesn’t  
exactly follow the ISO 15765 protocol. The above  
shows what the responses would look like with  
formatting on, and headers off. If you change either,  
the data exchange would look more like what we  
initially showed.  
>AT PB 81 0A  
OK  
Next, we’ll want to receive all messages with an ID  
of 7C0, and send with an ID (header) of 7B0:  
>AT CRA 7C0  
OK  
ELM329DSB  
Elm Electronics – Circuits for the Hobbyist  
www.elmelectronics.com  
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