[solved] at91sam7x512: external reset

gwynpen · **Joined:** Wed Jan 04, 2012 10:16 am **Posts:** 4

I adapted the SAM7 web server example (FreeRTOS V1.7.0) to my at91sam7x512/DP83848i based board (deRFgateway by Dresden Electronic). (Basically, I only had to adjust the memory size defines) The example runs so far, but there's a problem during the initialization of the PHY (DP83843i): the while loop which waits for end of hw reset

Code:

while( !( AT91C_BASE_RSTC->RSTC_RSR & AT91C_RSTC_NRSTL ) ) { __asm volatile ( "NOP" ); }

will loop endlessly. The problem does NOT occur when the SAM-ICE JTAG interface is connected! In fact, even when starting without SAM-ICE and connecting it after a while will end the loop. Afterwards, everything works fine (i.e. the EMAC).

I double checked low lever initialization etc. but couldn't find any problem there.

Any idea how to fix this?

Thanks!

CptTitanic · **Joined:** Sat Oct 30, 2010 6:04 pm **Posts:** 574

Make sure that the NRST pin isn't being driven high by some push-pull driver externally.

Code:

   /* Need to reset PHY -> 500ms reset */
   AT91C_BASE_RSTC->RSTC_RMR = (AT91C_RSTC_KEY & ((unsigned int)0xA5<<24)) |
                (AT91C_RSTC_ERSTL & (0x0D << 8)) | AT91C_RSTC_URSTEN;
   AT91C_BASE_RSTC->RSTC_RCR = (AT91C_RSTC_KEY & ((unsigned int)0xA5<<24)) |
                 AT91C_RSTC_EXTRST;

   /* Wait for end hardware reset */
   while (!(AT91C_BASE_RSTC->RSTC_RSR & AT91C_RSTC_NRSTL));

gwynpen · **Joined:** Wed Jan 04, 2012 10:16 am **Posts:** 4

I'm such a fool: I always switched off the SAM-ICE (removed USB cable) only but left the JTAG port connected to the board when testing "without" JTAG...

Everything works fine now, thanks for your hints!

[solved] at91sam7x512: external reset

Who is online