PIC18F4550 with Parallax USB datalogger via UART

[ahmedkhalaf]

I'm working on a Flash memory based datalogger using

Microchip PIC18F4550

and **broken link removed** which is based on **broken link removed**

I'm developing my prototype on MikroC so everything can be a piece of cake
My problem is interfacing the uC with the datalogger, and specifically the RTS/CTS hardware handshaking.

After around 12 hours of failing trials, I tried to tie datalogger's CTS to Gnd and datalogger's RTS to Vcc, but I get no data from it.

and the program is trapped on the first trial to receive responce from the datalogger

while(1)
{
if(UART1_Data_Ready())
{
UART1_Read_Text(RcvBuffer,"\r",Attempts);
break;
}
}


Can anyone provide clear info about that RTS/CTS hardware handshaking ?
Is it async ? or sync ?
Is it active low or active high ?

 

[brussel7]

I went about it slightly differently then coding the handshake, but perhaps this will help.

I connected the RTS pin to the CTS pin, making the device tell itself that its good to go.
I also connected the CTS pin to an analog input on an Arduino micro controller.

In the code while (analogread(A0) == 0)
{ delay (1); } //delays 1 ms.

Bridging the two pins initiates the data logger and CTS reads high when the data logger is ready for more data (~1.5/1023V). The CTS pin is also what controls the LED on the parallax data logger. After the handshake, put the drive in and it will flash red for a second and then go solid. When writing to it the light will also flash red when its clear to send and should turn off when the USB drive is removed.