It's funny....but kind of sucks at the same time. The issue is actually being caused by the optocoupler. The timing is well past anything it was designed to handle and the optocoupller can't make the pulses defined enough for the ecu to read them. Moving to a 6 pin version were we can go directly to the photocell to alter the "speed" that it can pulse may solve the issue or we may have to move to a mosfet but that will require some rework of the interrupts currently being used.Tazzi wrote:160plus wrote: 4X mode is working for monitoring currently but we are experiencing trouble transmitting larger blocks over 4x. We are getting an incorrect byte translation when we send the third part of the flash kernel we've been using. Some more tweaking of the circuit and timings and there's a good chance we'll have 4x working in the next week or two. While in 4x mode we can "Poke" the pcm so to speak to keep it in 4x mode and even after running for quite sometime the smaller blocks are still working fine so we figure it's close.
This was what I was referring to, where timings become so small and critical, that a single bit that is out will ruin an entire block send as then the VPW crc checksum will be invalid. Whether its the sending or receiving at 4x, its likely both are causing dramas, as your in the low microsecond level of timing
Id rather wait 8mins, then risk reliability for 4x.
This is the normal wave pattern we see while in 1x mode
This is the signal in 4x mode, as you can see sending more then just a very short message causes some pretty good distortion to the signal.