Actually it is writing 0xAA then 0x55. The second line of the disassembly is mvn (move negative). It loads the inverted value of 85=0x55 (0xFFFFFFAA) into r3. The next line stores the low order byte WFEED (-536870904=0xE0000008). Regards -Bill Knight R O SoftWare & http://www.theARMPatch.com On Tue, 06 Dec 2005 21:22:21 +0100, Ake Hedman, eurosource wrote: >I have found part of this problem. The GNU compiler translates >WDFEED = 0xAA; WDFEED = 0x55; >to >710 04c4 8E22A0E3 mov r2, #-536870904 >711 04c8 5530E0E3 mvn r3, #85 >712 04cc 0030C2E5 strb r3, [r2, #0] >713 04d0 8E22A0E3 mov r2, #-536870904 >714 04d4 5530A0E3 mov r3, #85 >715 04d8 0030C2E5 strb r3, [r2, #0] >i.e. just writing 0x55. This is done even if compiled with >optimization of. >Anyone know how to work around this? >Watchdog registers are currently defined as >// Watchdog >#define WDMOD (*((volatile unsigned char *) 0xE0000000)) >#define WDTC (*((volatile unsigned long *) 0xE0000004)) >#define WDFEED (*((volatile unsigned char *) 0xE0000008)) >#define WDTV (*((volatile unsigned long *) 0xE000000C)) >/Ake >Ake Hedman, eurosource wrote: >> >> Jim Parziale wrote: >> >> > Assuming you have the correct definitions for your symbols, the only >> > thing I >> > can think of is setting the timeout to the largest integer like that. >> > Maybe >> > you could try a different large integer? >> > >> > These are what you should be using: >> > WDEN = BIT(0) = 0x00000001 >> > WDRESET = BIT(1) = 0x00000002 >> > WDMOD = (uint8_t *)(0xE0000000) >> > WDTC = (uint32_t *)(0xE0000004) >> > WDFEED = (uint8_t *)(0xE0000008) >> >> Jim, >> >> yes my defines are the same and yes I have tested with other values for >> the watchdog period. According to the manual the watchdog timer should >> start when the 0xaa, 0x55 sequence is written but my problems are occurs >> as soon as I write to the WDMOD register. >> >> What situations can prevent the bootloader from working after a reset? >> >> /Ake >> >> > >> > ---------------------------------------------------------- >> > Jim Parziale >> > Email: nuncio.bitis@... >> > Malden, MA >> > ---------------------------------------------------------- >> > >> > On 12/6/05, Ake Hedman, eurosource <akhe@...> wrote: >> > > >> > > Hi all. >> > > >> > > I am trying to enable the watchdog but the result is a total hang >> of the >> > > board. Not even the bootloader is possible to reach after the >> crash and >> > > I have to reapply power with P0.14 low to get access to the botloader >> > > again. Reset is not enough. >> > > >> > > The code to initialize the watchdog is >> > > >> > > // initialize the watchdog timer >> > > WDTC = 0xffffffff; // 15000000; // One >> second >> > > = 15000000 >> > > WDMOD = WDEN | WDRESET; // Activate watchdog >> > > WDFEED = 0xAA; WDFEED = 0x55; >> > > >> > > I must have misunderstood the WD functionality. What am I doing wrong? >> > > In the above code the watchdog should not trigger until 5 minutes >> > > elapsed so even if a vector should be wrong the code that follow >> should >> > > run for a while but as soon as I write to the WDMOD register I get a >> > hang. >> > > >> > > /Ake >> > > >> > > -- >> > > --- >> > > Ake Hedman (YAP - Yet Another Programmer) >> > > eurosource, Brattbergavägen 17, 820 50 LOS, Sweden >> > > Phone: (46) 657 413430 Cellular: (46) 73 84 84 102 >> > > Company home: http://www.eurosource.se >> > > Kryddor/Te/Kaffe: http://www.brattberg.com >> > > Personal homepage: http://www.eurosource.se/akhe >> > > Automated home: http://www.vscp.org >> > > >> > > >> > >> > >> > [Non-text portions of this message have been removed] >> > >> > >> > ------------------------------------------------------------------------ >> > YAHOO! GROUPS LINKS >> > >> > * Visit your group "lpc2000 >> > <http://groups.yahoo.com/group/lpc2000>" on the web. >> > >> > * To unsubscribe from this group, send an email to: >> > lpc2000-unsubscribe@yahoogroups.com >> > <mailto:lpc2000-unsubscribe@yahoogroups.com?subject=Unsubscribe> >> > >> > * Your use of Yahoo! Groups is subject to the Yahoo! Terms of >> > Service <http://docs.yahoo.com/info/terms/>. >> > >> > >> > ------------------------------------------------------------------------ >> > >> >> >> -- >> --- >> Ake Hedman (YAP - Yet Another Programmer) >> eurosource, Brattbergavägen 17, 820 50 LOS, Sweden >> Phone: (46) 657 413430 Cellular: (46) 73 84 84 102 >> Company home: http://www.eurosource.se >> Kryddor/Te/Kaffe: http://www.brattberg.com >> Personal homepage: http://www.eurosource.se/akhe >> Automated home: http://www.vscp.org >> >> >> >> [Non-text portions of this message have been removed] >> >> >> >> SPONSORED LINKS >> Microprocessor >> <http://groups.yahoo.com/gads?t=ms&k=Microprocessor&w1=Microprocessor&w2=Microcontrollers&w3=Pic+microcontrollers&w4=8051+microprocessor&c=4&s=93&.sig=tsVC-J9hJ5qyXg0WPR0l6g> >> Microcontrollers >> <http://groups.yahoo.com/gads?t=ms&k=Microcontrollers&w1=Microprocessor&w2=Microcontrollers&w3=Pic+microcontrollers&w4=8051+microprocessor&c=4&s=93&.sig=DvJVNqC_pqRTm8Xq01nxwg> >> Pic microcontrollers >> <http://groups.yahoo.com/gads?t=ms&k=Pic+microcontrollers&w1=Microprocessor&w2=Microcontrollers&w3=Pic+microcontrollers&w4=8051+microprocessor&c=4&s=93&.sig=TpkoX4KofDJ7c6LyBvUqVQ> >> >> 8051 microprocessor >> <http://groups.yahoo.com/gads?t=ms&k=8051+microprocessor&w1=Microprocessor&w2=Microcontrollers&w3=Pic+microcontrollers&w4=8051+microprocessor&c=4&s=93&.sig=1Ipf1Fjfbd_HVIlekkDP-A> >> >> >> >> ------------------------------------------------------------------------ >> YAHOO! GROUPS LINKS >> >> * Visit your group "lpc2000 >> <http://groups.yahoo.com/group/lpc2000>" on the web. >> >> * To unsubscribe from this group, send an email to: >> lpc2000-unsubscribe@yahoogroups.com >> <mailto:lpc2000-unsubscribe@yahoogroups.com?subject=Unsubscribe> >> >> * Your use of Yahoo! Groups is subject to the Yahoo! Terms of >> Service <http://docs.yahoo.com/info/terms/>. >> >> >> ------------------------------------------------------------------------ >> >-- > --- >Ake Hedman (YAP - Yet Another Programmer) >eurosource, Brattbergavägen 17, 820 50 LOS, Sweden >Phone: (46) 657 413430 Cellular: (46) 73 84 84 102 >Company home: http://www.eurosource.se >Kryddor/Te/Kaffe: http://www.brattberg.com >Personal homepage: http://www.eurosource.se/akhe >Automated home: http://www.vscp.org >[Non-text portions of this message have been removed] > >Yahoo! Groups Links >
Message
Re: [lpc2000] Problem with watchdog
2005-12-06 by Bill Knight