Uart0 Not Sending Data

[maritza]

Posted on July 21, 2005 at 13:54

Uart0 Not Sending Data

[maritza]

Posted on May 17, 2011 at 12:07

I'm using the upsd3312d and i'm working with the Uart0 to send data to a serial port (r232) i have a transiver (ICL3225e) between the serial port and the uart, i can Reseive Data from the computer but i cannot send data to the computer.. i'm seen the data that go out of the Tx line in is always in low.. Here is the code that i'm using...

//1.2 #define Timer2_Set_BaudRate(BaudRate)

timer2_baud = (65536L - ( (FREQ_OSC * 125L) / (4L * UART0_BAUD_RATE)));

RCAP2L = (timer2_baud & 0x00FF);

RCAP2H = (timer2_baud >> 8);

//1.3 Configure Timer2: Mode-Timer, Interrupt-No, Start

//1.1 Select UART0 Baud Generator: TCLK-Timer2, RCLK-Timer2

T2CON = 0x34; //Set and start Timer2.

//sbit TF2 = T2CON^7; // Timer2 overflow flag.

//sbit EXF2 = T2CON^6; // External signal flag. Set when negative transition occur on T2EX and EXEN2=1.

//sbit RCLK = T2CON^5; // UART0 receive clock select. 0-Timer1, 1-Timer2

//sbit TCLK = T2CON^4; // UART0 transimit clock select. 0-Timer1, 1-Timer2

//sbit EXEN2 = T2CON^3; // Timer2 external signal (T2EX) enable.

//sbit TR2 = T2CON^2; // Start/Stop control

//sbit C_T2 = T2CON^1; // Timer/Counter select

//sbit CP_RL2 = T2CON^0; // Capture/Reload select

//2. Configure P3.0,P3.1 as UART0 pins

P3SFS |= 0x03;

// P3SFS = 0x01;

// Force On the Transiver for the RS-232

P3_2 = 1;

//3. Set UART0 operating mode

SCON = 0x50; // enable first serial UART & receiver

//4. Configure MCU Interrupt support

PS = 1; // high priority for UART interrupt

ES = 1; // Enable UART0 interrupt

EA = 1; // Enable global interrupt flag

I have a while loop in were i write to the SBUF but nothing happen...

I make some other test with the Mode 0 and it transmit but i need to change the baud rate, so this mode is not good form me...

Can you help me?

Thanks

:D

[ This message was edited by: maritzayanet on 16-07-2005 02:08 ]

[isabel_benitez]

Posted on May 17, 2011 at 12:07

Hello,

I had problems with this too and it was because of the oscillator. I was using a 36.000Mhz crystall in fundamental mode, I was supposing that the frequency was 36MHz but it was not true, it was 18.000Mhz. I had to put the crystall to work in third overtone mode so I really had 36.000MHz and know it works perfectly.

[danielh1]

Posted on May 17, 2011 at 12:07

What is your while loop? if you are waiting for the TI flag to go high, you wil wait for the eternity.

It goes high AFTER sending SBUF. At the beginning, you have to set it high yourself (SCON = 0X52).

Good luck, and keep smiling,

Daniel