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sci_tech_info [2015/01/25 12:40]
23.115.161.12 [TO DO LIST]
sci_tech_info [2015/03/10 11:32] (current)
shelgame
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 ==== SCI bus technical info ==== ==== SCI bus technical info ====
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 The communications specs are typical 8-N-1 at 0-5v (TTL) logic levels. However, it is setup with inverted logic. That means that a 0v registers as a binary '​1';​ and a 5v registers as a binary '​0'​. So, the interface you choose needs to be able to deal with this inverted logic. The ECU uses '​odd'​ baud rates - at least compared to a traditional PC serial port. Most ECU's start communications at 7812 baud, and then switch to 62500 for logging. Older LM's use lower baud rates, but still atypical. So, you also need to consider an interface that can communicate at these '​odd'​ baud rates, as well as switch baud rates after the port has been opened. The communications specs are typical 8-N-1 at 0-5v (TTL) logic levels. However, it is setup with inverted logic. That means that a 0v registers as a binary '​1';​ and a 5v registers as a binary '​0'​. So, the interface you choose needs to be able to deal with this inverted logic. The ECU uses '​odd'​ baud rates - at least compared to a traditional PC serial port. Most ECU's start communications at 7812 baud, and then switch to 62500 for logging. Older LM's use lower baud rates, but still atypical. So, you also need to consider an interface that can communicate at these '​odd'​ baud rates, as well as switch baud rates after the port has been opened.