Hope RFM95/98 power usage in sleep mode?

tomtor · March 27, 2017, 7:57pm

@petekmet The arduino-lmic lib sets the DIO ports to INPUT.

Did you change that to INPUT_PULLUP?

Still pulling my hair

petekmet · March 27, 2017, 8:30pm

My case wasn’t with arduino-lmic, just bare SPI to RFM95 on mbed and nRF51, so I was in full control of GPIO and in my responsibility. But in your case, on arduino, something like INPUT PULLUP could be what you need. Give it a try.

Epyon · March 27, 2017, 9:06pm

If you really want to save every last nanoamp it’s better to use external pullups than internal. Or use something more 21th century than a AVR .

tomtor · March 28, 2017, 6:21am

@Epyon

The irony is that currently my Atmega setup works but the 21th century STM32 not
I discovered that with all pins floating (STM32 Standby mode: 2 μA) the RFM95 uses 0.39mA.

The fundamental problem is that the STM32 uses in STOP mode (GPIOs in last setting, all clocks stopped except wakeup timer) in default GPIO state 0.7 mA.
With all pins programmed to analog input (according to the STM manual the most power efficient state) 0.018 mA in the same STOP mode.

So I am currently trading reduced leakage through the RFM pins for a less efficient STM32 GPIO setting. Pulling NSS low drops the current from 0.7mA to 0.4mA so the SPI configuration is probably the root cause, but I have not found a configuration with lower usage than 0.4mA for the STM32 setup.

Perhaps additional external pull up resistors are indeed the only solution.

Epyon · March 28, 2017, 9:21am

You’ve got yourself a real catch-22 there indeed. If you go for the analog input sleep option, using pull-ups will probably leak some current through the ADC input capacitor as well. Did you try setting all pins to digital input with internal pull-up OR digital output written low before going to sleep?

I use Freescale excuse me NXP Kinetis MK20 controllers, which are based on the same Cortex cores as the STM32, together with this excellent library for very satisfying results. The library saves the pin state, then puts all pins to output low and goes to sleep. When it wakes again, pin state is restored and the program continues as if nothing happened. The controller uses around 15µA during sleep.

tomtor · March 29, 2017, 10:02am

@Epyon

I’m a happy man, the total power consumption is at 12µA !

I discovered that the 5V tolerant pins used as DIO inputs consume a lot of current!
Disconnecting the unused DIO-2 and rewiring DIO-0/1 to 3.3V pins solved that.

Setting the SPI and other pins with the following code did the rest:

digitalWrite(PA5, LOW); // SCK
pinMode(PA5, OUTPUT);

digitalWrite(PA7, LOW); // MOSI
pinMode(PA7, OUTPUT);

pinMode(PA6, INPUT_ANALOG); // MISO

digitalWrite(lmic_pins.nss, LOW); // NSS
pinMode(lmic_pins.nss, OUTPUT);

// DIO Inputs
pinMode(PA3, INPUT_ANALOG);
pinMode(PB5, INPUT_ANALOG);

pinMode(lmic_pins.rst, INPUT_ANALOG);

// Serial
pinMode(PA9, INPUT_ANALOG);
pinMode(PA10, INPUT_ANALOG);

Epyon · March 29, 2017, 10:46am

Ah yes, 5V tolerant pins often have an internal level shifter that does draw significant current. Didn’t know the STM32 had those pins. Excellent work!

tomtor · March 29, 2017, 2:23pm

@epyon Another issue was the USB pullup on PA12 which I missed. It accounted for at least 0.15 mA.

Thanks for all the feedback!

Charles · April 7, 2017, 12:23pm

Guys,

I faced this kind of problem when played with ULPNode, In my case I was powering down RFM module with a mosfet to be sure 0 power will be consumed but had problem with port config pull up/down, I solved with the following code

The one part interesting for you is the part after f (!power)

/* ======================================================================
Function: powerRadio
Purpose : expose driver method of power or unpower the RF module 
Input   : true to power on false to power off
Output  : true if powered and module found
Comments: -
====================================================================== */
boolean ULPNode::powerRadio(uint8_t power)
{

  // do we need to power up the sensors
  if ( power) {
    uint8_t status_mask = 0;

    // From here and with latest Arduino version we have a problem
    // Arduino SPI library now check if SPI has already been initialized
    // if so, init is not done again and as we changed SS pin and some 
    // others to have full Low Power, we need to enhance back all as it
    // should be done in a real Spi init EACH time.
  
    //SPCR |= _BV(SPE);

    // Warning: if the SS pin ever becomes a LOW INPUT then SPI
    // automatically switches to Slave, so the data direction of
    // the SS pin MUST be kept as OUTPUT.

    // set back CSN pin with pullup (it was input)
    digitalWrite(RF_CSN_PIN, HIGH); 
    // now set it as output high
    pinMode(RF_CSN_PIN, OUTPUT); 
    digitalWrite(RF_CSN_PIN, HIGH); 

    // Power Up Modules SPI 
    power_spi_enable();  

    // Enable back SPI and set as MASTER
    SPCR |= _BV(SPE);
    SPCR |= _BV(MSTR);

    // MISO pin automatically overrides to INPUT.
    // By doing this AFTER enabling SPI, we avoid accidentally
    // clocking in a single bit since the lines go directly
    // from "input" to SPI control.
    // http://code.google.com/p/arduino/issues/detail?id=888
    // Not needed because we didn't changed these pins 
    //pinMode(SCK, OUTPUT);
    //pinMode(MOSI, OUTPUT);

    // power ON VCC the radio module
    setDevice(DEVICE_RF_ON);

    // RF module settle delay 
    sleepQuickWake( WDTO_15MS );
    //delay(15);

    if (_radio_type == RF_MOD_NRF24)
      status_mask = RF_NODE_STATE_NRF24;
    if (_radio_type == RF_MOD_RFM69)
      status_mask = RF_NODE_STATE_RFM69;

    // Init the radio driver with moteino config
    if (!driver.init()) {
      // Radio state not OK
      _status &= ~status_mask;
      return false;
    }

    // Radio is okay
    _status |= status_mask;

    // Specific init for RFM69
    if ( _status & RF_NODE_STATE_RFM69) {
      RH_RF69 * prf69_drv = (RH_RF69 *) &driver;

      // Moteino settings
      prf69_drv->setModemConfig(RH_RF69::FSK_MOTEINO);
      prf69_drv->setPreambleLength(3);
      // Copied from LowPowerLab 
      prf69_drv->spiWrite(RH_RF69_REG_29_RSSITHRESH, 220);
      prf69_drv->spiWrite(RH_RF69_REG_3D_PACKETCONFIG2, RH_RF69_PACKETCONFIG2_RXRESTARTDELAY_2BITS | RH_RF69_PACKETCONFIG2_AUTORXRESTARTON);

      // default moteino Frequency For 433 MHz 
      prf69_drv->setFrequency(433.0);
    }

    // Specific init for NRF24
    if ( _status & RF_NODE_STATE_NRF24) {
      // Defaults after init are 2.402 GHz (channel 2), 2Mbps, 0dBm
      //nrf24.setChannel(1))
      //nrf24.setRF(RH_NRF24::DataRate2Mbps, RH_NRF24::TransmitPower0dBm))
    }
  }
  
  // So this is a power off
  if ( !power) {
    // This will configure the radio pins for correct low power mode
    driver.sleep();

    // We're going to sleep, we've done our job no need to be awake by
    // RF module firing up a IRQ when we're in power down (can cause trouble?)
    //detachInterrupt(digitalPinToInterrupt(RF_IRQ_PIN));

    // Once agin, very important even if we power off the module, because 
    // of pullup, module still powered via SS/IRQ Pin. if we don't do this
    // even if VDD of RFModule set to "float" using mosfet, current is get
    // drawn by other pins pullup (CS or IRQ), so disable pull up
    pinMode(RF_CSN_PIN, INPUT); 
    digitalWrite(RF_CSN_PIN, 0); 

    // Disable SPI device
    SPCR &= ~_BV(SPE);
    
    // unpower SPI of Arduino
    power_spi_disable();  

    // unpower RF module
    setDevice(DEVICE_RF_OFF);
  }

  return (true);
}

Charles · April 7, 2017, 12:27pm

And for those interested here the code to disable all ATMega328 device for low power

Remember that I power down devices (I2C and SPI) using a mosfet to enable/disable them so all VDD pin of devices is then left float

/* ======================================================================
Function: disableCPUDevices
Purpose : disable Atmel integrated devices (for low power)
Input   : -
Output  : - 
Comments: - 
====================================================================== */
void ULPNode::disableCPUDevices(void)
{
  // Disable ADC 
  ADCSRA &= ~_BV(ADEN)  ; 

  // disable Analog comparator  
  ACSR |= _BV(ACD); 
  
  // Disable digital input buffers on all ADC0-ADC5 pins
  //DIDR0 = 0x3F;    

  // set I2C pin as input no pull up
  // this prevent current draw on I2C pins that
  // completly destroy our low power mode

  //Disable I2C interface so we can control the SDA and SCL pins directly
  TWCR &= ~(_BV(TWEN)); 

  // disable I2C module this allow us to control
  // SCA/SCL pins and reinitialize the I2C bus at wake up
  TWCR = 0;
  pinMode(SDA, INPUT);
  pinMode(SCL, INPUT);
  digitalWrite(SDA, LOW);
  digitalWrite(SCL, LOW);  

  /*
  power_adc_disable();
  power_usart0_disable();
  power_spi_disable();  
  power_twi_disable();
  power_timer0_disable(); 
  power_timer1_disable();
  power_timer2_disable();
  */

  power_all_disable();
}

bluejedi · April 10, 2017, 3:33pm

Even easier to minimize power use during sleep mode is to define unused IO pins as output (commonly used on ATmega/‘Arduino’).

BoRRoZ · April 28, 2018, 9:29pm

23 posts were merged into an existing topic: Big STM32 boards topic

bluejedi · April 28, 2018, 9:17pm

@BoRRoZ @everyone

I think the STM32 related posts should be placed in the Big STM32 boards topic
Maybe above STM32 posts can be moved to the STM32 topic (where they are easier to find and don’t hijack this topic).

BoRRoZ · April 28, 2018, 9:29pm

done… let’s keep this topic for the RFM95/98.

I stumbled across this conversation about enabeling the PA_BOOST to have +20dBm

schallb · February 4, 2019, 12:24pm

I tried to combine deepsleep of atmega328 and RFM95 controlled via LMIC library.

at first i do a JOIN to the LoraWAN nework and store the session information in RAM
after an initial data send i put the CPU to deepsleep via
LowPower.powerDown(SLEEP_8S, ADC_OFF, BOD_OFF);
then i call
LMIC_shutdown();
every nth wakeup i call
LMIC_reset();
and recall the last session settings via
LMIC_setSession (netid, devaddr, nwkKey, artKey);
additionally i set the same parameters as i did in EV_JOINED event
LMIC_setClockError(MAX_CLOCK_ERROR * 1 / 100); //Relax RX timing window
LMIC_setAdrMode(1); //enable ADR
LMIC_setLinkCheckMode(1);
LMIC_setDrTxpow(DR_SF9, 15);
finally i trigger a new packet via
os_setCallback(…)

So far this seems to work well, but there is a question left: is the sequence
LMIC_setClockError(MAX_CLOCK_ERROR * 1 / 100); //Relax RX timing window
LMIC_setAdrMode(1); //enable ADR
LMIC_setLinkCheckMode(1);
LMIC_setDrTxpow(DR_SF9, 15);

to much, or do i need to set additional parameters?

The question might sound stupid because it seems to work fine, but i want to be on the safe side…

Amedee · February 4, 2019, 1:18pm

I never shutdown/reset LMIC while sleeping (or save anything from the session)…
LMIC_setDrTxpow(DR_SF9, 15): there is probably no point of setting Data Rate if you do ADR; also if you are in Europe, 14dBm is the maximum you can use (It is not important as LMIC doesn’t do anything with that anyway)

schallb · February 4, 2019, 1:23pm

So, have you measured your power consumption with/without shutdown?
If I have not done a mistake there was a significant difference!

Amedee · February 4, 2019, 3:39pm

I have not, less than 0.7 µA was good enough for me…

jchen747 · February 24, 2019, 9:24pm

Hi,

I’m now using the MSP430 and RFM95. When I was testing the total current of the whole system. I put RFM95 into sleep and put MSP430 pin’s output low. The system cost 0.5mA which is much high. What I’m sure of is that MSP430 cost only a few uA. I also guess the DIO cost some power. But I didn’t find anything in the datasheet to configure the DIO.
If anyone can help, that will be so grateful.

Beginner · August 27, 2019, 5:21am

Hey i am currently trying to use msp430 and rfm98 for data transmission and i am kinda stuck so can you please help me by sending your code and the library you are using for rfm98 module