Update rate of ALDL

[TurboTim]

What actually makes the update rate of the ALDL so slow? I hear that directscan runs at about 32 frames/sec (directly from the computer) while scanmaster, turbolink, autoXray,...(anything that plugs in through the ALDL) all run at 1 frame every 1.15 sec. So, why can't the ALDL put out the same 32 frames/sec instead of the slow 1 frame/1.15 sec?

 

[kenmosher]

DirectScan runs at 18 fps (not 32).... it's hooked directly to the ECM bus and "listens" to the CPU talking to memory. That's why it hooks to the fragile edge connector.

The others are at the ALDL, which is a SERIAL data stream (like for a modem...except different ). It is limited to the rate and size that the ECM sends out via a totally different method.

 

[TurboDave]

Like Ken said, the ALDL port is serial data. It runs at 160 baud (slowwwwww), and each sensor (byte) is sent out one after the other. Which is why it takes about 1.5 seconds to get through all the transmitted bytes and start another round. That's why you can only see the data bytes updated every 1.5 seconds.

 

[dthrock]

Card Edge

I wouldnt call the connection to the ecm fragile. Its more sturdy/thicker than any PC card you will find now and Ive never broken one of those. You would have to really be ham-fisted to cause any damage to that connector putting a cable onto it.

Getting it cleaned up is another story. If you use a sharp edge on it you could cut or damage the contacts on it so be careful.

David

 

[kenmosher]

That's what I mean by fragile ... not the physical strength of the board, but the fact that you can damage it, push the connector on too far, get RMI interference, etc.

It's the method (which is just the nature of the beast ...) not the materials.