[En-Nut-Discussion] Problem with stdin on DBGU

[Bernd Walter]

On Fri, Jun 04, 2010 at 07:58:51PM +0200, Bernd Walter wrote:
> On Fri, Jun 04, 2010 at 06:43:54PM +0200, Bernd Walter wrote:
> > Controller is AT91SAM7S321
> > Nut/OS is 4.9.8.
> > 
> > My main function starts with:
> >         // Initialize the console
> >         uint32_t cons_baud = 115200;
> >         NutRegisterDevice(&DEV_CONS, 0, 0);
> >         freopen(DEV_CONS_NAME, "w", stdout);
> >         if (freopen(DEV_CONS_NAME, "w", stderr) == NULL) {
> >                 printf("open stderr failed\n");
> >         }
> >         if (freopen(DEV_CONS_NAME, "r", stdin) == NULL) {
> >                 printf("open stdin failed\n");
> >         }
> >         _ioctl(_fileno(stdin), UART_SETSPEED, &cons_baud);
> > 
> > With:
> > #define DEV_CONS        devDebug
> > #define DEV_CONS_NAME   "dbgu"
> > 
> > Then after many successfull printf I have the following code:
> >         for(;;) {
> >                 char *cp;
> >                 static char buf[128];
> >                 buf[0] = '\0';
> >                 printf("ready!\n");
> >                 fflush(stdout);
> >                 NutThreadYield();
> >                 if (fgets(buf, sizeof(buf), stdin) == 0) {
> >                         printf("<EOF>\n");
> >                         fflush(stdout);
> >                         NutThreadYield();
> >                         continue;
> >                 }
> >                 printf("<got something>\n");
> >                 fflush(stdout);
> >                 NutThreadYield();
> >                 if ((cp = strchr(buf, '\r')) != 0) {
> >                         *cp = 0;
> >                 }
> >                 if ((cp = strchr(buf, '\n')) != 0) {
> >                         *cp = 0;
> >                 }
> >                 if (buf[0] == 0) {
> >                         continue;
> >                 }
> > 
> >                 if (strncmp(buf, "memory", strlen(buf)) == 0) {
> >                         printf("%u bytes RAM free\r\n", (u_int)NutHeapAvailable());
> >                         continue;
> >                 }
> > 
> >                 printf("List of commands follows\n");
> >                 printf("memory\tQueries number of RAM bytes free\n");
> >         }
> > 
> > With fgets the system just restarts.
> > I've debugged it up to _read and it turned out that dev->dev_read is
> > NULL.
> > Not surprising that calling code at address 0 restarts the system.
> 
> Oh - I've just notice in debug_at91.c that there really is no read
> function.
> That's very unexpected for me :-(
> Is there any special reason for this?
> I know that is hasn't some of the very special features that USART
> have and that it shares an interrupt, but otherwise it is very similar
> to USART.
> The reason I want to use this interface is that I already have a
> usecase for the USART and that the DBGU is already wired for flashing
> via SAM-BA.
> 
> I also noticed devDbguAt91 - ist useable?
> There is a #define NUT_DEPRECATED at start - sounds not.

It compiles and work :-)
The NUT_DEPRECATED still irritates me though.

-- 
B.Walter <bernd at bwct.de> http://www.bwct.de
Modbus/TCP Ethernet I/O Baugruppen, ARM basierte FreeBSD Rechner uvm.