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recommend method for initiating reset from software

Chris Korda
Prodigy 20 points
Other Parts Discussed in Thread: AM1808

On the AM1808, what is the recommend method for initiating a reset via software? Hard reset would be preferable. The goal is for the boot loader (in SPI flash) to execute. I tried branching to address zero, but it didn't work, possibly because the interrupt vectors are remapped. Is it necessary to program the watchdog and/or the PSC, or is there a more direct way? I'm currently using LogicPD's eval board.

Best regards,

Chris

  • 0
    Prodigy 20 points

    I answered my own question though it took me a while. I enclose my solution so hopefully no one will ever worry about this again!


    #include "evmam1808.h"
    #include "evmam1808_timer.h"

    #define    WDEN    0x00004000
    #define    WDKEY1    0xA5C60000
    #define    WDKEY2    0xDA7E0000

    void Reboot()
    {
        // might want to mask all interrupts first...
        TMR1->GPINT_GPEN = 0;
        TMR1->GPDATA_GPDIR = 0;
        TMR1->INTCTLSTAT = 0;
        TMR1->EMUMGT = 0;
        TMR1->TGCR = 0;        // reset
        TMR1->TCR = 0;        // reset
        TMR1->TGCR = TIMMODE_64BIT_WDOG;    // set watchdog mode
        TMR1->TIM12 = 0;    // zero initial count
        TMR1->TIM34 = 0;   
        TMR1->TGCR |= TIM34RS | TIM12RS;    // unreset
        TMR1->PRD12 = 0;    // zero period for immediate reset
        TMR1->PRD34 = 0;
        TMR1->WDTCR = WDKEY1 | WDEN;    // make watchdog pre-active
        TMR1->WDTCR = WDKEY2 | WDEN;    // make watchdog active
    }

  • 0 in reply to Chris Korda
    Intellectual 295 points

    Chris Korda said:

    I answered my own question though it took me a while. I enclose my solution so hopefully no one will ever worry about this again!


    #include "evmam1808.h"
    #include "evmam1808_timer.h"

    #define    WDEN    0x00004000
    #define    WDKEY1    0xA5C60000
    #define    WDKEY2    0xDA7E0000

    void Reboot()
    {
        // might want to mask all interrupts first...
        TMR1->GPINT_GPEN = 0;
        TMR1->GPDATA_GPDIR = 0;
        TMR1->INTCTLSTAT = 0;
        TMR1->EMUMGT = 0;
        TMR1->TGCR = 0;        // reset
        TMR1->TCR = 0;        // reset
        TMR1->TGCR = TIMMODE_64BIT_WDOG;    // set watchdog mode
        TMR1->TIM12 = 0;    // zero initial count
        TMR1->TIM34 = 0;   
        TMR1->TGCR |= TIM34RS | TIM12RS;    // unreset
        TMR1->PRD12 = 0;    // zero period for immediate reset
        TMR1->PRD34 = 0;
        TMR1->WDTCR = WDKEY1 | WDEN;    // make watchdog pre-active
        TMR1->WDTCR = WDKEY2 | WDEN;    // make watchdog active
    }

    Thanks Chris,

    I'm going to keep that in mind for our project, although so far I find that using the LINUX "reboot" command seems to work on the AM1808evm board OK.

  • 0 in reply to Mellissa Dalby
    Expert 1985 points

    this is the common way to do this to trigger watch dog reset the cpu.. 

    might put a while (1); dead loop at the end of the function.