UART Full duplex communication coding problem

[sysysy]

Hi,

with the datasheet of PIC 16F877A, state that support in full duplex communication.

I mange to make the half duplex communication working between my 2 MCU. but when come to full duplex , everything become not working.

Can anyone tell me why and guide me to solve this problem?

***
I am using the polling method in transmit and receive data for both main program of MCU. Someone suggest me using buffer with interrupt method, but i have no idea at all to implement this.

 

[xxtigerxx]

to work in full duplex communication you must use the interrupt signals and no wait for the flags.

if you use the interrupts i do not think you will have any problem.

 

[sysysy]

May i know in my interrupt service routine,

can i tranmit 2 byte data go out in sequence?
what i mean is just like

#INT_TBE
void transmit_isr()
{
     fputc(0xAA) ;//transmit the first byte header
     fputc('C');    //transmit the actual of data character 'c'
}

I doubt that this can work since the interrupt being call when the TXIF is set (mean the TXREG register is empty)

But why there is a compulsory to use interrupt since the receive and the transmit will be never conflict. they don't share any register or anythigs. But why make the whole program conflict?

 

[xxtigerxx]

the program you wrote it will work..

when you are in a interrupt the global interrupt is disabled unless you enable it.
The routine will transmit the 2 bytes and then after the interrupt routine will call again.

 

[sysysy]

It never work, i tried in many days already...many way i tried also not working...
the conclusion i made is the PIC not able to manipulate the transmitter and receiver uart together...

but i don't know deal with my coding part.... super FRUSTRATED

Tiger, anyway thanks for your reply and help....

 

[hussain_kiet]

what happens when you transmit only one char in the ISR..?
it will be helpful if you post the receive section and main program as well...