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SubjectRegarding USB-RS485 Cable Manufacturer: FTDI SerialNumber: FTU6Z938
Date

Hello Greg,
I have purchased a USB-RS485 Cable Manufacturer: FTDI SerialNumber: FTU6Z938.
And I have written a user space program to communicate with my Rs-485 device at the
other end.The device at the other end expect 1 address byte with mark parity and rest of
the bytes with space parity.


Below is the userspace code which I have used for setting the Mark and Space parity bit.

// Send the first byte with mark parity-
attr.c_cflag |= PARENB;
attr.c_cflag |= CMSPAR;
attr.c_cflag |= PARODD;
tcsetattr(fd, TCSADRAIN, &attr);
write(fd, buff, 1); // It writes the address byte
// Send the rest with space parity

attr.c_cflag |= PARENB;
attr.c_cflag |= CMSPAR;
attr.c_cflag &= ~PARODD;
tcsetattr(fd, TCSADRAIN, &attr);
write(fd,buff+1,( length-1));
I can see the Data going out on the Scope when I terminate the userspace program using
Control+ C. But the device at the other end is not responding.

Kindly tell me Whether It can be done from userspace or I have to modify the device driver.


Regards,
Raj.



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