[En-Nut-Discussion] NutOS Dbgu Interrupt

Ulrich Prinz uprinz2 at netscape.net
Wed Jan 20 20:58:31 CET 2010


I started to write a full featured USART driver for the DBGU myself some 
month ago. I didn't finish cause of missing time. But I remember the 

The registers of the DBGU are the same as for other full features 
USARTs. Only the bits representing not supported things of the DBGU are 
unused. Therefore you can use the same but reduced USART routines as for 
the other USARTs.

But in the interrupts, there is a difference as the standard ports have 
an interrupt for them self (like your timers). The DBGU Interrupt is 
handled through the system interrupt. So you cannot write your own 
interrupt routine called by an interrupt, you have to write one that is 
called from the system interrupt routine, or lets call it the system 
interrupt manager.

THe code can be a copy'n'paste from the USART drivers, then you throw 
out any code that handles not supported things. DBGU can only used 8 
Bits and 1 stop bit. It has no hardware handshake support, but you can 
keep the part of the GPIO emulated RTS/CTS signals if you like.

I have my code somewhere, may be I can pass it over to you. My interest 
was to enable RX on the DBGU what is missing in the NutOS 
implementation. I would like to use the DBGU interface for configuration 

Best regards, Ulrich

kafka85 schrieb:
> Hi,
> I'm using Nut/OS 4.8.5. I'm trying to create my own routine on DBGU receive interrupt. Can you guide me how to do that?
> I succesfully created timer interrupt as follows:
> void InitApiTimer(void) {
>     compare_value = local_ZBTO;
>     outr(AIC_IECR, _BV(TC1_ID));
>     outr(PMC_PCER, _BV(TC1_ID));
>     outr(TC1_CCR, TC_CLKDIS);
>     outr(TC1_IDR, 0xFFFFFFFF);
>     inr(TC1_SR);
>     outr(TC1_CMR, TC_CLKS_MCK32);
>     outr(TC1_RC, local_ZBTO);
>     outr(TC1_CCR, TC_CLKEN);
>     outr(TC1_IER, TC_CPCS);
>     NutRegisterIrqHandler(&sig_TC1, ApiTimerIntr, 0);
>     NutIrqSetPriority(&sig_TC1, 7);
>     NutIrqEnable(&sig_TC1);
>     outr(TC1_CCR, TC_SWTRG);
> }
> My DBGU setup routine is as follows:
> void debug_init(AT91PS_DBGU paramDbgu, AT91PS_PIO paramPio, uint32_t pinMask,
>         uint8_t periph, uint32_t baud) {
>     pDbgu = paramDbgu;
>     paramPio->PIO_PDR = pinMask;
>     if (periph == 0) {
>         paramPio->PIO_ASR = pinMask;
>     } else {
>         paramPio->PIO_BSR = pinMask;
>     }
>             | AT91C_US_TXDIS;
>     pDbgu->DBGU_MR = AT91C_US_PAR_NONE | AT91C_US_CHRL_8_BITS;
>     pDbgu->DBGU_BRGR = AT91F_US_Baudrate(MCK, baud);
>     //enable interrupt source
>     //pDbgu->DBGU_IER = AT91C_US_RXRDY;
>     pDbgu->DBGU_CR = AT91C_US_RXEN | AT91C_US_TXEN;
> }
> I'd like to create my own DBGU interrupt routine in the same manner as my timer interrupt.
> _______________________________________________
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