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Mike
01-10-2009, 12:35 PM
Hi,

I need to do a serial rs232 communication between an ADuC831 and an ARM9 at a buad rate of 230400 buad. I plan to do this in half duplex mode, so :
1. Can this be achieved using only the Tx, Rx and GND signals for communication.

2. If no then what kind of handshaking concepts will i have to use to achieve this (@ 230400 baud).

Thanks

debu
01-10-2009, 01:32 PM
@Mike: Welcome to RI :)


1. Can this be achieved using only the Tx, Rx and GND signals for communication.

Yes, it can.

Regards,

Debu :)

Mike
01-12-2009, 05:37 PM
what about the second point. Do we require handshaking signals at 230400 baud. I intend to use it in half duplex mode, i.e only one controller(module) will be transmitting at any given time.

shashak
01-12-2009, 09:56 PM
Do we require handshaking signals at 230400 baud.

certainly notnas far your controller able handle/support 230400 baud by default, only minor issues could be that of proper connection and efficient code as at any lower baud , btw what is the part no. of your ARM9 microcontroller, ??

Mike
01-13-2009, 10:05 AM
I am already using an ADuC831 in my module which uses a MAX3232 for serial. The ARM9 that i'm planning to use is an Atmel AT91SAM9RL64. The ADuC831 datasheets specify that it can perform a serial at 230400 baud MAX. and similarily, the MAX3232 that i'm using can perform at a MAX of 250Kbits/s.

Mike
01-14-2009, 05:21 PM
'IF' i need to use the RTS / CTS signals on both the controllers as handshaking signals, tell me if i'm wrong by saying :

RTS /CTS of both the controllers are cross cabled.

when Controller 1 wants to TRANSMIT data to Controller 2, it will ASSERT the RTS signal and wait/listen to the CTS input. The Controller 2, on receiving this RTS Signal on it's CTS input, will ASSERT it's RTS signal, which is connected to the CTS input of Controller 1 to indicate that it's ready to RECEIVE data. Then the Controller 1 will start the serial transmission.

A similar thing happens when Controller 2 wants to transmit data to Controller 1.

Mike
01-16-2009, 02:51 PM
could anyone reply to this :::

"'IF' i need to use the RTS / CTS signals on both the controllers as handshaking signals, tell me if i'm wrong by saying :

RTS /CTS of both the controllers are cross cabled.

when Controller 1 wants to TRANSMIT data to Controller 2, it will ASSERT the RTS signal and wait/listen to the CTS input. The Controller 2, on receiving this RTS Signal on it's CTS input, will ASSERT it's RTS signal, which is connected to the CTS input of Controller 1 to indicate that it's ready to RECEIVE data. If the first Controller does not recieve a CTS then it will wait for a timeout and then re-assert the RTS.

A similar thing happens when Controller 2 wants to transmit data to Controller 1."

karthikprasad
07-23-2009, 08:32 PM
Why dont u try exploiting the asynchronous feature of the serial communication feature present in both mcus.There isnt even one mcu in the current market which is devoid of asynchronous serial comm ie in AVR lingo UART that basically eliminates the handshaking part rite