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Fantastic that a windows alternative to X-Lap has been written.


I will happily give it a try. Have sent a PM.

Also for anyone that wants to run the software and has not bought X-Lap and the PC-Unit, PM me and I will send you info and prices on my Carrera to USB lead.

Rich
 

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QUOTE (poolschool @ 1 Mar 2009, 10:45) <{POST_SNAPBACK}>On that note, most computers running WIN 98 have a DB9 serial port on them, as the data from the lap counter is serial, do you need to go through a serial to USB converter, as the FTDI based one, or just go straight from the lap counter to the DB9 serial port?

You either need to use a Serial to USB converter like the FTDI chip that my cables are based on, or you can go to the Serial port. This will need to be through a level convrter such as the Max232 range of chips. It will not work when directly connected, the Lap Counter has 5V level signals and the PC requires RS232 levels.

Rich
 

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Hi Bruce

Interesting stuff and not something I had considered.

To what degree is loss of communication & dropped comm a problem with the CU? Is this just an issue with the new CU or also the old lap counter?

Having a quick read about USB Transfer Size & Latancy it seems that the way things work is that with the standard setup the chip waits for the buffer to be full (4096 Bytes) or when the Latency Timer times out (16mS from the last transfer) So if we are typically seeing less that 4096 Bytes, then it will probably be the the Latency Timer will be determining when transfers are made?

So with your settings of 64 Bytes & 48mS it is likely that it is now the Transfer size that is now running the show? Was there a reason why you turned the Latency up?

Probably worth doing a bit of maths on the typical packet sizes to see what is going on? I will also have a think about this is the context of Scalextric & Ninco, although I have not heard of any comms issues there may be a gain to be had, particularily with the new Scalextric Powerbase, C7042, which like Carrera is very comms intensive with the PC constantly polling the Powerbase with small packets.

FTDI document AN 107 worth a read, in particular 6.2 & 6.3.
Also see AN232B-04

Rich
 

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I suspect this is one of those tricky times where all the theory is not as good as the practical solution.
I guess also to some degree the tuning of the parameters is compensating for a flaw in the CU firmware, as in all honesty it should not matter within reason what these variables are set to, and the unit should definitely not hang?

Do we know if the CU has the same problems with the Carrera PC Unit or just with the FTDI cable?

Rich
 

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CP210x should be fine, it has VCP divers available and it's functionality looks very similar to the FTDI FT232, although personally I would have stuck with the tried & tested FTDI device. Assume you have a complete assembly / cable as opposed to a chip? You will of course need to fit a Mini Din to plug up to the CU.

Rich
 

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Bruce's software is a PC program like SSDC, not a firmware upgrade.

Hopefully Bruce will be back, we have all had the occasional attack from a disgruntled customer.

Rich
 
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