Watchdog .NETMF

NETMF & Gadgeteer
1

I as using the .NETMF 4.3 SDK to write firmware for STM32F405. I am trying to implement the hardware watchdog. I understand that the Microsoft.SPOT.Hardware watchdog is not working as expected and according to the guide I need to use the using GHIElectronics.NETMF.Hardware.LowLevel watchdog, however, I am failing to locate it and when I try to use it, it is saying that the namespace could not be found. Please assist with locating and integrating it to my project. Thanks.

2

This is from many, many years go so I do not remember exactly but I think the implementation was only on G120 and G400 and not on open source projects.

3

I did exactly this about 8 years ago. I believe I just looked up the Watchdog registers in the manual for the CPU and set a few of the bits using that LowLevel API. Then in my program’s main loop or in a separate thread with a loop, I would set the keep alive bit. If my program ever froze, the keep alive bit would not get set and the whole thing would reboot. I can’t find that code anymore, but here is an old post:

4

Looks like the intervalSeconds never got implemented, but I think this worked. I think you initialize, then call reset every few seconds. If you don’t call reset, it reboots. Try this:

public static class WatchdogTimer
{
    const UInt32 PERIPH_BASE = 0x40000000;
    const UInt32 IWDG_BASE = PERIPH_BASE + 0x3000;  // Independent watchdog (IWDG)
    static Register IWDG_KR = new Register(IWDG_BASE + 0x00);
    static Register IWDG_PR = new Register(IWDG_BASE + 0x04);
    static Register IWDG_RLR = new Register(IWDG_BASE + 0x08);
    static Register IWDG_SR = new Register(IWDG_BASE + 0x0C);

    static void Initialize(int intervalSeconds)
    {
        IWDG_KR.Write(0x5555);  // Enable Access to Watchdog Registers
        IWDG_PR.SetBits(0x07);  // Set Divider to /256
        IWDG_RLR.SetBits(0xFFF); // Set starting number for countdown in watchdog 0xFFF is about 32 seconds
        IWDG_KR.Write(0xCCCC);  // Start the watchdog timer!!!
    }

    static void Reset()
    {
        Debug.WriteLine("Resetting watchdog");
        IWDG_KR.Write(0xAAAA);
    }
}