Connecting a USB<->rs232(uart) module to the de-0 nano via GPIO

Ok, so I'm starting to get a bit crazy:D Atm, I just want to send a 8 bit vector from my computer, "not" it, and send it back.

So I started with creating a SOPC

https://www.alteraforum.com/forum/attachment.php?attachmentid=6556

And now I have no idea, do I use the new component option inside the SOPC(with the "not" logic, I attached the file but it's really simple) or outside the SOPC. I currently have something like this

https://www.alteraforum.com/forum/attachment.php?attachmentid=6557

Which shows me that I can connect the UART to the GPIO pins, but how do I then send the received data(from the uart) to my logic block? Reading the manual that came with the de-0 nano didn't really help as they just used the sopc to run simple C program on the de-0 nano while using the Jtag UART. So my main problem would be how can I access the converted UART data? Peering into the vhdl file generated by the SOPC builder there is about a million signals and my guess would be that one of them would be used as the converted data from the UART?

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Based on the fact that you want to use the serial module (rather than JTAG).

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Well, since it's the more complicated idea maybe I can learn more from it:)

Thanks for all the newbie info,

Fred

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Since you comment you are a newbie, I'll provide some feedback on your design proposal and offer an alternative.

Your project/proposal:

What is the task? Are you responsible for the FPGA communications, or is that just a means-to-an-end? Is the main task related to the polynomial coefficients and whatever those coefficients are controlling?

As far as the communications aspect goes, your solution would work fine, however, it may involve more work than is really necessary. Here's what you would do:

1. Connect the two boards together.

a) The serial board looks like some sort of FTDI breakout board with USB and a header. It should be receiving power from the USB port, so there should be *no* reason for you to connect power pins from that board to the DE0-nano.

b) Check that your RS232 board output is 3.3V logic - not 5V logic (the DE0-nano cannot handle 5V signals).

c) Connect the TX and RX pins from your serial board to two GPIO pins on your DE0-nano, and connect a ground pin between the two boards (so that they both agree on voltages).

2. Create an FPGA system containing a NIOS II processor, a UART, and your custom logic and connect that UART to the GPIO pins.

3. Write NIOS II software to receive data over the serial port, and write the coefficients into your custom logic.

4. Write the host software to send data to the NIOS II.

While all this is pretty straightforward, since you are new to this, it might take you a while to get to grips with all the details.

An alternative implementation is to implement the communications using the USB-Blaster connection that already exists between your board and your PC. Read through this tutorial

http://www.alterawiki.com/wiki/using_the_usb-blaster_as_an_sopc/qsys_avalon-mm_master_tutorial

The tutorial contains all the code you need for communications with a Qsys or SOPC System.

Continue to ask questions and the readers of this forum will provide feedback.

Cheers,

Dave

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Hi Dave,

Could you please provide me links for Step 3 and 4 that you mentioned? really appreciate

2. Create an FPGA system containing a NIOS II processor, a UART, and your custom logic and connect that UART to the GPIO pins.

3. Write NIOS II software to receive data over the serial port, and write the coefficients into your custom logic.

4. Write the host software to send data to the NIOS II.

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Ok, so I'm starting to get a bit crazy:D Atm, I just want to send a 8 bit vector from my computer, "not" it, and send it back.

So I started with creating a SOPC

http://www.alteraforum.com/forum/attachment.php?attachmentid=6556&stc=1

And now I have no idea, do I use the new component option inside the SOPC(with the "not" logic, I attached the file but it's really simple) or outside the SOPC. I currently have something like this

http://www.alteraforum.com/forum/attachment.php?attachmentid=6557&stc=1

Which shows me that I can connect the UART to the GPIO pins, but how do I then send the received data(from the uart) to my logic block? Reading the manual that came with the de-0 nano didn't really help as they just used the sopc to run simple C program on the de-0 nano while using the Jtag UART. So my main problem would be how can I access the converted UART data? Peering into the vhdl file generated by the SOPC builder there is about a million signals and my guess would be that one of them would be used as the converted data from the UART?

Well, since it's the more complicated idea maybe I can learn more from it:)

Thanks for all the newbie info,

Fred

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Hi Fred,

Could you please tell me how did you access the converted UART data finally? Thank you

The easiest way was to get the ALTERA university program (UP) IP cores. I added a RS232 UART component (from the UP) to a Qsys system and then used the HAL drivers (#include <altera_up_avalon_rs232.h>) supplied with the UP to receive and send data with a simple nios ii program.

Open up the uart device:

alt_up_rs232_dev *rs232_0_dev;

rs232_0_dev=alt_up_rs232_open_dev("/dev/rs232_0");

I then wait for data from the UART:

while((alt_up_rs232_get_used_space_in_read_FIFO(rs232_0_dev))==0)

{

//wait for a character from the UART

}

Once a byte of data is ready i read it:

alt_up_rs232_read_data(rs232_0_dev, &in_buffer[index1], &parity_read1)

Writing data is similar, wait for free space in the UART outgoing buffer and send data:

while(alt_up_rs232_get_available_space_in_write_FIFO(rs232_0_dev)==0)

{

//printf("waiting for space in out fifo\n");

}

//printf("after waiting for space in out fifo\n");

if(alt_up_rs232_write_data(rs232_0_dev,temp1[index2])==0)

{

}

A MUCH more elegant solution would be using nios ii interrupts, this simple example "blocks" the program until a specific amount of data is read (you have to wait for data before the program can do other things). In the university program folder you can find more examples using the UART core.

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The easiest way was to get the ALTERA university program (UP) IP cores. I added a RS232 UART component (from the UP) to a Qsys system and then used the HAL drivers (#include <altera_up_avalon_rs232.h>) supplied with the UP to receive and send data with a simple nios ii program.

Open up the uart device:

alt_up_rs232_dev *rs232_0_dev;

rs232_0_dev=alt_up_rs232_open_dev("/dev/rs232_0");

I then wait for data from the UART:

while((alt_up_rs232_get_used_space_in_read_FIFO(rs232_0_dev))==0)

{

//wait for a character from the UART

}

Once a byte of data is ready i read it:

alt_up_rs232_read_data(rs232_0_dev, &in_buffer[index1], &parity_read1)

Writing data is similar, wait for free space in the UART outgoing buffer and send data:

while(alt_up_rs232_get_available_space_in_write_FIFO(rs232_0_dev)==0)

{

//printf("waiting for space in out fifo\n");

}

//printf("after waiting for space in out fifo\n");

if(alt_up_rs232_write_data(rs232_0_dev,temp1[index2])==0)

{

}

A MUCH more elegant solution would be using nios ii interrupts, this simple example "blocks" the program until a specific amount of data is read (you have to wait for data before the program can do other things). In the university program folder you can find more examples using the UART core.

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Hi Fred,

Thanks for your reply. What I want to do is Nios processor reads data from FPGA, Nios transmits the data to serial port and plot graph real time using Maltab,using de0 nano. I do not need to read data from serial port.

1. I used the following code to access the UART component I created in Qsys, I connected the txdata pin to the oscilloscope and it shows nothing, i am wondering why couldn't I use IOWR_ALTERA_AVALON_UART_TXDATA(UART_BASE, txdata); to transmit data to UART?

2. Quate "Writing data is similar, wait for free space in the UART outgoing buffer and send data:" When you said, send data, do you mean IOWR_ALTERA_AVALON_UART_TXDATA(UART_BASE, txdata)?

I really hope to get some hints from you, been struggling for a while, thanks for your kind help.

# include "altera_avalon_uart_regs.h"

# define UART_BASE 0x00002000

int main (void)

{alt_u16 status, rxdata=0,aa=0, txdata=0;

while (! (status & 0x0040)) // Wait for transmission completion

status = IORD_ALTERA_AVALON_UART_STATUS (UART_BASE);

printf("status= %.2f V \r\n", (float) status);

rxdata = 5; // assuming I get this data by accessing sdram in Nios

txdata = rxdata;

IOWR_ALTERA_AVALON_UART_TXDATA(UART_BASE, txdata);

printf("txdata= %.2f V \r\n", (float) txdata);

return 0;}