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Hello I'm working on Android App that can read data from CAN bus. The interface I'm using is ELM327. The problem is that this interface uses Bluetooth. So I cannot read all the data from CAN bus because after half of the sec the buffer is full. The the interface is v. 1.4.7. And I am using Bluetooth terminal on Android. The commands I used:

ATZ -> to reset the interface

ATH1 -> set header 

ATS1 -> set spaces 

ATL1 -> Linefeeds on 

ATAL -> Sets long message

Then I want to set delay for lets say 1 sec

ATST FF -> Set timout to 1 sec

ATSP 6 -> I'm using CAN so this is protocol no 6

ATCM 170 -> setting mask

ATCF 176 -> set filter

ATMA -> Monitor all

And using that there is no delay.. I will be grateful for any help! Thank you M.

Matt199
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  • If the buffer is full you either must increase the baudrate with ATBRD and you must set filters to get only the data you are interested in. Use ATMR or ATMT instead of ATMA. – Elmue May 23 '20 at 14:12

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I don't think you will be able to use ATMA with anything but USB-interfaces. All those ELM327-clones have too small buffers. If you insist on using wireless interfaces, you might want to try an interface based on the STN1110 chip, which has at least four times RAM.

DrMickeyLauer
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  • Do you have any link to prove this theory? If the ELM327 sends all monitored data immediately to the USB cable what does it need a big buffer for? – Elmue May 23 '20 at 14:08
  • @Elmue I said it will work with USB interfaces. I'm not so sure about Bluetooth and WiFi ones. – DrMickeyLauer May 24 '20 at 12:03
  • USB Full speed has12 Mbit/s. The speed of bluetooth (up to 24MBit/s) is far higher than the maximum baudrate of the ELM327 (500 kBaud). So your theory of a too small buffer does not apply. Even if there was a bigger buffer: What would it help? It would only take longer until the bigger buffer is also full. I cannot imagine of a connection to the PC which should not be able to transmit 500kBaud – Elmue May 26 '20 at 13:57
  • You are talking PCs. I am talking mobile systems, such as smartphones operating with Bluetooth Low Energy, which struggles achieving a sustainable 500kBaud. – DrMickeyLauer May 26 '20 at 15:38
  • OK. But this does not change the fact that a bigger buffer does not solve this problem. – Elmue May 26 '20 at 22:36