Reply by Roberto Espinosa ●November 8, 20032003-11-08
Dear Sir or Madam,
I am using Dsk 5402 board and I want to connect two of them via Uart Rs232
directly without any hardware between the two boards, except by a cable with two
db9 connectors in its extremes. Could you answer these doubts?

1.- Where are adressed the Brg and Iir registers?
2.- Which connections among the pins of rs232 port should I do to connect
directly both boards?Which C code should I use?
3.- Could you say to me if these are the connections among the pins of the port
and signals?
\/
\1 2=rxd 3=txd 4=dtr 5=gnd /
\ 6=dsr 7=rts 8=cts 9=ci /<-----it is the front view of rs232
port
\------------------------------/
I make you this question because I am executing the following code and I
observing data in pin 2 with my oscilloscope and they should be observe in pin
3:
void emision(void)
{
const int putchar = 'A';
uart_reset();
uart_init();
uart_setup(UART_BAUD_9600, UART_WORD8, UART_STOP1, UART_DISABLE_PARITY,
UART_FIFO_ENABLE, UART_NO_LOOPBACK);
while(1)
{
uart_fputc(putchar);
}
}
4.- Does the pin rxd is used to recieve data from dsp in order to send to the
channel or to recieve data from channel to be read by Dsp?
5.- In relation with the previous code, which is the purpose of the fifo abiliy
and the loopback?
6.- Could you send me a program in C code to communicate the two boards. I want
to transmit data of 8 or 16 bits. I want a program to know when the transmitter
is able to write and the receiver knows when has received data.
That is to say, when I want to transmit data from rs232 to the external of
the board:
6.1.-which instruction must I use?
6.2- Must I check any flag to know if the transmission of this data has
finished?
6.3.-In reception, which flag does my code have to check if it has
received the data?
6.4.-With Which intruction can I access to these data?
Where can I find more information about Uart?
I think any of the manuals I have provide the enough information about Rs232.
Please, help me, I have not very much time.

Yours faithfully
Roberto Espinosa
Espeleolectronic Devices, Spain. ---------------------------------
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