Re : IT'S WORKS ! (how to drive serial port? I want to write and to read data on the line CTS, RTS and DTR)

[Davide P.]

Hi,

I'm using the ComSetEscape from NI RS232 library and I'm able to reach the frequency of 41 kHz on the SCL line. Maybe it depends on the CPU but I noticed some differences in the OpenComConfig function behaviour:

opening the com with baudrates from 110 to 115200 the SCL line frequency is around 32kHz, but with 128000 and 256000 the frequency increases up to 41 kHz.

At 41 kHz goes 30% faster...  

Regards, Davide.

[tigroo92]

41kHz is a nice speed !

But I think that the speed achieved by controlling the SUBD speed relies mainly on the COM hardware characteristics.

- COM port of the computer :fastest solution.

- USB COM port : lower speed, as you have to include the time for the USB protocol created by the virtual COM port driver (*)

But I2C works, even at 50Hz ! It is not a problem to control some LEDs, but to program a 1Mb memory, it will take a long time !

(*) I had a similar problem to emulate a JTAG bus using a USB FDTI chip used for a parallel port.

Regards,

Pascal