1mhz hardware



  • I recently flashed an arduino pro mini bootloader to 1mhz. This in the end did what I wanted, which was low power. However, I am still noticing something odd and believe I have missed something.

    I have this line in my loop

    whichbutton = sleep(digitalPinToInterrupt(2),LOW,digitalPinToInterrupt(3),LOW,3600000);//86400000);
    

    Doesn't seem to be waking up as expected. It does wake up, but not quite on the hour like I would have expected. But it still wakes up on interrupt which is the important thing.

    The other thing I am curious about is I have the following for checking my battery. Which works, but I have a question regarding the percent. Is the percent based on the actual drop out voltage? For instance, I have a 3v battery. My fuses are set to 1.8v for dropout. Is the battery percentage basing 0% at 1.8v or 0v?

    void CheckBattery()
    {
        // battery stuff
       // get the battery Voltage
       int sensorValue = analogRead(BATTERY_SENSE_PIN);
       #ifdef MY_DEBUG
       Serial.println(sensorValue);
       #endif
       
       // 1M, 470K divider across battery and using internal ADC ref of 1.1V
       // Sense point is bypassed with 0.1 uF cap to reduce noise at that point
       // ((1e6+470e3)/470e3)*1.1 = Vmax = 3.44 Volts
       // 3.44/1023 = Volts per bit = 0.003363075
       
       int batteryPcnt = sensorValue / 10;
    
       #ifdef MY_DEBUG
       float batteryV  = sensorValue * 0.0029325513196481;
       Serial.print("Battery Voltage: ");
       Serial.print(batteryV);
       Serial.println(" V");
    
       Serial.print("Battery percent: ");
       Serial.print(batteryPcnt);
       Serial.println(" %");
       #endif
    
       if (oldBatteryPcnt != batteryPcnt) {
         // Power up radio after sleep
         sendBatteryLevel(batteryPcnt);
         oldBatteryPcnt = batteryPcnt;
       }
    
    
    
    
    }```
    
    @Nca78

  • Mod

    @Jason-Brunk said:

    It does wake up, but not quite on the hour

    Can you be more explicit? How much time is there inbetween wakeups? The watchdog will always be a bit off, but it should only be a few %


  • Hero Member

    Did you change the board definition within the Arduino IDE so that the code is compiled for 1 MHz? If not, the timing wont match. :)

    According battery:

    100 % = Vmax = 3.44 Volts
    0 % = 0 V


  • Hardware Contributor

    Hello, no idea with the wake up time, I didn't check it at 1MHz, but it should not vary as it's based on the watchdog timer which is always at 128KHz, and not related to the main clock frequency and multiplier.

    For the battery level do you use a divider ? That's useful if you have a booster, but for a CR2032 directly connected to Vcc the most simple way is to measure the supply voltage. Please note that my measurement is not exact as value should be adjusted to the exact voltage of the "1.1V" reference voltage of the atmega.

    #include <SystemStatus.h>
    // Parameters for VCC measurement
    const int VccMin        = 2000;  // Minimum expected Vcc level, in Volts. At 2V the cell should be dead
    const int VccMax        = 2900;  // Maximum expected Vcc level, in Volts.
    SystemStatus vcc();
    int LastBatteryPercent = 200; // so we are sure to send the battery level at first check
    
        int currentBatteryPercent = SystemStatus().getVCCPercent(VccMin, VccMax);
        if (currentBatteryPercent != LastBatteryPercent) {
            LastBatteryPercent = currentBatteryPercent;
            sendBatteryLevel(currentBatteryPercent);
        }
    
    


  • @TimO Here is my definition in my boards.txt

    ## Arduino Pro or Pro Mini (1.8V, 1 MHz) w/ ATmega328
    ## --------------------------------------------------
    pro.menu.cpu.1MHzatmega328=ATmega328 (1.8V, 1 MHz)
    
    pro.menu.cpu.1MHzatmega328.upload.maximum_size=30720
    pro.menu.cpu.1MHzatmega328.upload.maximum_data_size=2048
    pro.menu.cpu.1MHzatmega328.upload.speed=9600
    
    pro.menu.cpu.1MHzatmega328.bootloader.low_fuses=0x62
    pro.menu.cpu.1MHzatmega328.bootloader.high_fuses=0xD4
    pro.menu.cpu.1MHzatmega328.bootloader.extended_fuses=0x06
    pro.menu.cpu.1MHzatmega328.bootloader.file=atmega/ATmegaBOOT_168_atmega328_pro_1MHz.hex
    
    pro.menu.cpu.1MHzatmega328.build.mcu=atmega328p
    pro.menu.cpu.1MHzatmega328.build.f_cpu=1000000L
    


  • @Nca78 yes currently using a voltage divider. if i go to measuring the supply voltage alone that will get rid of the extra components I may not be needing atleast for this node.

    I will try your example. Thanks!



  • @Yveaux Ok. so it checked in at 3:17am this morning. it did not check in again until 1:58 this afternoon. :)


  • Mod

    @Jason-Brunk that's almost 10 hours. My guess is that the timer is 8x off (if the code expects 8Mhz but is running at 1Mhz). Try recompiling with 1MHz board settings or divide the time by 8 in the sketch)



  • @mfalkvidd Ill reflash it. Just wondering if there is something in the code I should change to tell it it's running at 1mhz or if that's something that is supposed to just work based on the clock timing


  • Mod

    @Jason-Brunk I think the Arduino IDE is supposed to handle all that if the correct board is selected. I know that timings are off if I select 16MHz pro mini in the IDE and then flash to a 8MHz Arduino. It is also easily noticeable on the serial monitor, which will require a setting of twice the baud rate set in Serial.begin. I have never built a 1MHz node though.


  • Hardware Contributor

    @Jason-Brunk why not falsh your node for internal 8mhz for instance, and then use 1Mhz in sketch ? On my side, I prefer this way..and it works for me at least.
    when the node is not sleeping, and radio is not sleeping in RX mode for instance, there is no big saving to do this, only atmel consumption is low, radio is not..but if your radio is sleeping, yep it's interesting but I don't really see advantage to start node at 1Mhz as the radio does not sleep at startup and does the protocol stuff.


  • Hardware Contributor

    @Jason-Brunk said:

    Just wondering if there is something in the code I should change to tell it it's running at 1mhz or if that's something that is supposed to just work based on the clock timing

    Clock settings are determined by the"fuses". What's your tool for fuses and bootloader programming? Are you sure you programmed the fuses as in your "boards.txt" above?


  • Hardware Contributor

    @m26872 said:

    @Jason-Brunk said:

    Just wondering if there is something in the code I should change to tell it it's running at 1mhz or if that's something that is supposed to just work based on the clock timing

    Clock settings are determined by the"fuses". What's your tool for fuses and bootloader programming? Are you sure you programmed the fuses as in your "boards.txt" above?

    My understanding was that the "burn bootloader" function of the Arduino IDE will also write the fuses, no ?

    From Arduino website :
    "How does it work?

    The "Burn Bootloader" commands in the Arduino environment use an open-source tool, avrdude. There are four steps: unlocking the bootloader section of the chip, setting the the fuses on the chip, uploading the bootloader code to the chip, and locking the bootloader section of the chip"


  • Hardware Contributor

    @Nca78 True. And I suppose you've also double checked the verbose output from that process.
    Can't help you further. I would try soft 1MHz instead then, as @scalz suggested.



  • Ok. So I got back in town and reflashed my bootloader. Claims it's running 1mhz now. No regulator, no leds. Even in sleep mode I am sitting at about 1.66ma. Which in deep sleep mode that seems really high. Considering the capacity of a coin cell i am looking at changing out about once every 2 weeks with no use.

    Any thoughts? Recommendations? Just can't seem to get this running low power enough. Not sure if my hardware is junk or what. But i would take any recommendations or tests to see how to get this working since i have a small stack of these pro minis


  • Hardware Contributor

    There's obviously a problem, I'm at about 1/1000 of that in sleep mode, you're sure your multimeter is not mistaking the unit ? ;)
    I have cheap pro minis too, the < 2$ kind.

    1mA+ in sleep mode sounds like a voltage regulator still connected, or the IC not sleeping, at least not in power down mode like when using the MySensors function. Are you sure you didn't leave a #define by mistake (like activating the repeater function with #define MY_REPEATER_FEATURE) that would prevent the atmega from sleeping ?



  • I checked, no REPEATER on.

    Here is the code for my loop()

    int whichbutton = 0;
    
    whichbutton = sleep(digitalPinToInterrupt(2),LOW,digitalPinToInterrupt(3),LOW,86400000);
    
    switch (whichbutton) {
      case digitalPinToInterrupt(2):
          {//off
          send(msg_light.set(0),true);
          wait(300);
          break;
          }
      case digitalPinToInterrupt(3):
          {//on
          send(msg_light.set(1),true);
          wait(300);
          break;
          }
        
      } 
    sleep(250);
    CheckBattery();
    

    It's not running that over and over for sure. Otherwise I would see the battery value publishing regularly to the broker.

    I broke the regulator off and the LEDs.
    This is the one I have.
    https://www.sparkfun.com/products/11114

    I don't think the multimeter is misreading it. I can see the battery percentage dropping over the course of a day so it definitely seems like it's pulling more mA than it should sleeping.


  • Hardware Contributor

    @m26872 said:

    @Nca78 True. And I suppose you've also double checked the verbose output from that process.

    In case someone doesn't believe the Arduino docs ;)
    This is at the beginning of the bootloader writing process in Arduino IDE:

    Writing | ################################################## | 100% 0.01s
    
    avrdude: 1 bytes of efuse written
    avrdude: verifying efuse memory against 0x06:
    avrdude: load data efuse data from input file 0x06:
    avrdude: input file 0x06 contains 1 bytes
    avrdude: reading on-chip efuse data:
    
    Reading | ################################################## | 100% 0.01s
    
    avrdude: verifying ...
    avrdude: 1 bytes of efuse verified
    avrdude: reading input file "0xde"
    avrdude: writing hfuse (1 bytes):
    
    Writing | ################################################## | 100% 0.01s
    
    avrdude: 1 bytes of hfuse written
    avrdude: verifying hfuse memory against 0xde:
    avrdude: load data hfuse data from input file 0xde:
    avrdude: input file 0xde contains 1 bytes
    avrdude: reading on-chip hfuse data:
    
    Reading | ################################################## | 100% 0.01s
    
    avrdude: verifying ...
    avrdude: 1 bytes of hfuse verified
    avrdude: reading input file "0x62"
    avrdude: writing lfuse (1 bytes):
    
    Writing | ################################################## | 100% 0.00s
    
    avrdude: 1 bytes of lfuse written
    avrdude: verifying lfuse memory against 0x62:
    avrdude: load data lfuse data from input file 0x62:
    avrdude: input file 0x62 contains 1 bytes
    avrdude: reading on-chip lfuse data:
    

  • Hardware Contributor

    @Nca78
    The docs won't tell you if the process fails. The verbose output will. :wink:



  • hmmm. ok so I have verified I am writing the 1mhz boot loader.

    My multimeter says when it's sleeping i am still running at 1.5mah

    I have my openhab system tracking the battery usage. IN 6 days I have lost 30% of the battery and it's been in sleep mode.

    || *Time* || *Value* ||
    || 2016-08-14 19:29:27 || 100 ||
    || 2016-08-15 19:07:57 || 80 ||
    || 2016-08-15 19:11:18 || 81 ||
    || 2016-08-15 19:12:48 || 83 ||
    || 2016-08-15 19:13:14 || 76 ||
    || 2016-08-15 19:13:17 || 84 ||
    || 2016-08-15 19:13:56 || 80 ||
    || 2016-08-15 19:16:48 || 78 ||
    || 2016-08-19 15:07:57 || 76 ||
    || 2016-08-19 15:10:09 || 80 ||
    || 2016-08-19 15:12:43 || 79 ||
    || 2016-08-19 15:13:49 || 82 ||
    || 2016-08-19 15:14:20 || 84 ||
    || 2016-08-20 11:44:01 || 69 ||
    || 2016-08-20 11:44:23 || 48 ||
    || 2016-08-20 11:44:31 || 71 ||
    
    
    

    Any thoughts? Any recommendations on maybe a replacement pro mini that will for sure run at <1mah?


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