P2040: How to send/receive data on second UART

[gouravjain]

Hi All,

P2040 do support 4 UARTs. Out of 4 i'm using two, UART0 and UART1.

Both UARTs are working as a console dev in standalone case.

by changing followings,

1) RCW value.

2) CONFIG_CONS_INDEX  1 or 2 in the /include/configs/P2041RDB.h file in the u-boot source.

3) root=/dev/ram rw console=ttyS0,115200 or root=/dev/ram rw console=ttyS1,115200

Till here everything is fine.

But when i tried to make UART1 as a console and UART0 just to send/receive normal data, UART1 is working properly while no transaction in UART0.

Wrote a small application for sending data in UART0,

appl: 

char data[] = "aa";
int fd, i;
fd = open("/dev/ttyS0", O_RDWR);
if(fd <0)
           printf("Error\n");
else
          printf("Success\n");

for (i=0; i<10; i++){
         write(data, sizeof(data), 1, fd);
}

Expected data on UART0 terminal(rs-232), But not coming.

Would be very thankful if someone help me out.

regards,

Gourav

[Pavel]

Use termios API.

Look at the following examples for using console as serial port under Linux:

https://stackoverflow.com/questions/6947413/how-to-open-read-and-write-from-serial-port-in-c

https://www.tldp.org/HOWTO/pdf/Serial-Programming-HOWTO.pdf

http://man7.org/linux/man-pages/man3/termios.3.html

https://en.wikibooks.org/wiki/Serial_Programming/Serial_Linux

https://control.com/thread/1026196999

and drfaw attention on the following page for serial port locking:

https://blog.mbedded.ninja/programming/operating-systems/linux/linux-serial-ports-using-c-cpp/

Have a great day,
Pavel Chubakov

[Pavel]

It looks like that your standalone application uses UART0 and UART1 from DUART1. The UART0 and UART1 use the same Internal Interrupt Number. Check your interrupt procedure.

See the Table 24-1 of the P2040 Reference Manual.

See simple program example for DUART in the attached file. It is code for the MPC8548. Similar code can be used on the P2040.

Have a great day,
Pavel Chubakov

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[gouravjain]

Hi Pavel,

Thanks for your attention on my query.

Yes. Application does use UART0 and console dev prints are in UART1, with same interrupt.

Why should i go for DUART2??

My application prints are not reflecting on UART0.

regards,

Gourav