K8055 faster

Kits PC Related Projects
1

Some time ago I purchased a K8055 (as built) for driving my elapse time metering system,
Worked well with Win7 but was disappointed in the speed.
Also the recently upgrading to the DLL version 5 did not bring improofment,
Is it possible to change the PIC16 chip for the PIC18 chip to get better speed??
Delivered by Velleman??
Or are other ways???

Thanks in advance Anema

2

[quote]Is it possible to change the PIC16 chip for the PIC18 chip to get better speed??[/quote] It is possible to change the PIC16 to PIC18, but you have also do some other modifications on the board and get the program for the PIC18.
Please see: viewtopic.php?f=3&t=7480

[quote]Delivered by Velleman??[/quote]No, programmed PIC and/or firmware are not delivered.

[quote]Or are other ways???[/quote]Alternatively you may purchase the K8055N or VM110N. They are faster than the K8055.
There are some speed test results in this thread: viewtopic.php?f=3&t=8672

3

The PIC18 devices are indeed faster. The responsiveness of the K8055 can be improved up to 10x with such a conversion.

However, before going into all of that we should make sure that your problem is actually caused by the lack of speed of the card itself.

How fast is your program reading data from the K8055? If it doesn’t read every 10 ms or faster, your program will see changes to the inputs of a K8055 with a delay of over 300 ms. The reason for this is that the card is sending a status message (HID report) every 10 ms. Windows holds these messages in a ring buffer and when your application reads that data, it always gets the oldest available. That ring buffer is by default 32 messages long. If it is completely full, Windows throws away the oldest message to make room for a new one.

Since the original K8055 sends at a fixed interval of 10 ms, you cannot measure any more precise than that with it. Changing to a PIC18 device with a drop-in compatible firmware (I can help you to put such thing together), you can get this down to 1 ms precision. This is a limitation of USB and unfortunately sometimes there are glitches in the USB communication and nothing happens on the bus for several hundred milliseconds. If you cannot repeat the measurement in such a case, then just switching to a PIC18 alone isn’t getting you the reliable measuring system you are looking for.

There is still more that can be done. But before discussing that we should know a little more about your measuring system and your precision requirements.

4

Mr Willow Grove thanks for your comment, here are some requirements:

In the elapse time measuring system the K8055 has to do 2 main tasks:

  • polling of the inputs if there are start or finish pulses ( the K8055 has no interrupt !!)
  • to make readable the the time between start and finish on a big numerick LED or flip/flap 4 or 5 character display. The time between is running in seconds ( max. 99 sec ). When finishing the total elapse time should be presented in 0.01 seconds.
    About 100 software instructions are needed to give the next result on the display , that takes now more than 1 sec. , what is not acceptable.

Side remark >> I also bought two different USB2.0 to RS232 conversion sticks/cables but they were in the best case 100 times slower then the original serial port on my old laptop.

Do you have some suggestins how to solve this problem???

thanks in advance Oebele Anema

5

No, at this point I do not have any suggestions to you.