UART 16550 vs standard UART

Hi all,

just tried to get the 16550 UART to work at all, but no output so far. I tried to implement, what is in the the "ug_embedded_ip" manual, but so far no luck.

Is there anything obvious missing, or wrong:

# include <stdio.h>

# include <stdlib.h>

# include <sys/ioctl.h>

# include <sys/termios.h>

# include <fcntl.h>

# include <string.h>

# include <unistd.h>

# include <sys/time.h>

# include <time.h>

# include "system.h"

# include "altera_16550_uart.h"

# include "altera_16550_uart_regs.h"

# define BUFSIZE 512

char TXMessage[BUFSIZE] = "Hello World, UART16550 sending\n";

int UARTDefaultConfig(UartConfig *Config)

{

Config->stop_bit = STOPB_1;

Config->parity_bit = NO_PARITY;

Config->data_bit = CS_8;

Config->baudrate = BR115200;

Config->fifo_mode = 0;

Config->hwfc = 0;

Config->rx_fifo_level= RXFULL;

Config->tx_fifo_level= TXEMPTY;

return 0;

}

int UARTBaudRateTest()

{

UartConfig *UART0_Config = malloc(1*sizeof(UartConfig));

altera_16550_uart_state* uart_0;

uart_0 = altera_16550_uart_open ("/dev/a_16550_uart_0");

UARTDefaultConfig(UART0_Config);

altera_16550_uart_write(uart_0, &TXMessage, strlen(TXMessage), 0);

usleep(1000);

free(UART0_Config);

return (0);

}

int main()

{

int result=0;

result = UARTBaudRateTest();

}

Thanks!

Hi,

What you mean by replacing the standard UART?

How about changing the BSP settings (stdin, stdout, stderr) to 16550 UART?

Are you trying to printf output through 16550 UART IP instead of RS232 UART IP?

I had a look at using the 16550 UART. In the end I found it much easier to use this one:-

http://www.alterawiki.com/wiki/fifoed_avalon_uart

It is exactly the same to use as the standard Altera UART but offers buffering, higher speed, RS485 driver enable + lots more. Well worth a look.

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Hi,

What you mean by replacing the standard UART?

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yes!

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How about changing the BSP settings (stdin, stdout, stderr) to 16550 UART?

Are you trying to printf output through 16550 UART IP instead of RS232 UART IP?

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Exactly. I saw in another post, that you should be able to simply replace the "uart0" in the BSP_HAL editor,

but in the setttings HAL/Common stdin/stdout/stderr, the only entry is "none" and the a_16550_uart_0 can't be selected.

Do I have to rename the instance of "a_16550_uart_0" to "uart_0" in qsys?

Thanks!

Hi,

I suspect you observed "none" in the settings due to the Qsys generated files are not refreshed/synced with your SBT.

Try reload the .sopcinfo file and create new BSP. You do not have to rename as the settings should reflect the name in Qsys.

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Hi,

I suspect you observed "none" in the settings due to the Qsys generated files are not refreshed/synced with your SBT.

Try reload the .sopcinfo file and create new BSP. You do not have to rename as the settings should reflect the name in Qsys.

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I tried that too, and the 16550_uart doesn't show :(

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Did you export those UART signals in Qsys?

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Yes, they also show up in the .bdf file and are connected there ...

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Have you tried if JTAG UART works?

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No. I had the "standard" UART in before, got my application working, but needed one with a FIFO. So tried to get the 16550-UART to work, without success.

What I'm really trying is to get the RSU working (application note 741), so my NIOS system is pretty simple, basically using the AN-741 template, and replacing

the UART in it with the 16550-UART. Any chance anybody else can try it?