STM32?

[VaZso]

@gohan Regarding of battery powered system...

From STM32CubeMX power consumption calculator, it has the following current requirements:

In RUN mode:

• at 72MHz bus frequency, it needs 27 mA
• at 16MHz and HSI PLL, it needs 6.8 mA
• at 8 MHz and HSI, it needs 4 mA
• at 1 MHz and HSI, it needs 900 μA
• at 125 kHz and HSI, it needs 480 μA

---

In STANDBY mode with all clocks off, it needs 2 μA

---

In SLEEP mode:

• at 125 kHz bus frequency and HSI, it needs 410 μA
• at 1 MHz bus freq. and HSI, it needs 440 uA
• at 8 MHz, it needs 600 μA

---

Enabling the following peripherals, additional consumptions are (as for example):

• GPIOA needs 833.75 nA
• GPIOD needs 816.25 nA
• I2C needs 1.25 μA
• SPI1 needs 590 nA
• TIMER1 needs 2.92 μA
• TIMER2 needs 4.06 μA
• TIMER4 needs 3.99 μA
• USART1 needs 1.49 μA
• USART3 needs 1.53 μA
• USB needs 2.22 μA
• Window watchdog needs 312.5 nA
• Independent watchdog needs 1.71 μA
• ADC1 needs 162.19 μA

These are just some examples, not all possibilities and frequencies are listed here...

There are also lower power STM32 series anyway.

[gohan]

I'm curious because I saw these boards few months ago but I figured that community support was still in the early stages so I kind of didn't pay much attention to them and I preferred old but tested technology 😁

[alowhum]

The patch has just been added to the Mysensors Development branch, so it's easier to try out.

I've created a guide on how to get started on the SMT32Duino forum.

[alowhum]

Heh, the STM32 doesn't have a digital pin 2 it seems. Where is the NRF supposed to connect to instead?

[mfalkvidd]

@alowhum looks like PA3: https://github.com/mysensors/MySensors/pull/795/commits/ac432acca3d7c58eb7c8f569dc562860605ea09f#diff-58c572256858a37808c4ebd0922b4060R50

[alowhum]

That's odd. I thought I had it just figured out. I'm about to test this at the top of a sketch:

#define MY_RF24_CE_PIN PB0
#define MY_RF24_CS_PIN PA4
#define MY_RF24_MOSI_PIN PA7
#define MY_RF24_MISO_PIN PA6
#define MY_RF24_SCK_PIN PA5
#define MY_RF24_IRQ_PIN PB10

The fun thing is all the pins are almost in a row. Almost. And if the IRQ is A3, then one more pin would line up..

According to this image the IRQ is pin PB10 though:
http://wiki.stm32duino.com/images/a/ae/Bluepillpinout.gif

[mfalkvidd]

@alowhum sorry I misread your question. Don't know why, but I didn't see that you were talking about the NRF.

IRQ is not used for the NRF on Arduino, so I supposed it is not used for STM32 either. There is nothing about IRQ in https://github.com/mysensors/MySensors/pull/795/commits/ac432acca3d7c58eb7c8f569dc562860605ea09f#diff-cf14b6301beb3a4dbaded9b95bb190feR487

[alowhum]

Really? On the Arduino nano I'm always connecting it to pin 2. It says to do so in the guide?

Anyway, I haven't been able to get it to work. Perhaps some of the developers van shed some light on how it's supposed to work?

[tbowmo]

@alowhum

Its first in recent (develop branch?) that interrupt usage with nRF24L01 have been enabled, and only in certain scenarios.

[tekka]

@alowhum The MySensors RF24 driver is a polling driver (unless RX queuing is enabled), hence no IRQ required.

I've successfully tested the RF24 radio with this wiring on a BluePill board using MySensors 2.2.0-beta:

CLK -> PA5
MISO -> PA6
MOSI ->PA7
CSN -> PA4
CE -> PB0

do not forget to set:

#define MY_RF24_CE_PIN PB0

[alowhum]

Hmm, that's pretty much what I had.

Could you perhaps share your example sketch?

// It's working now! Turns out I had to set the radio to low power..

[mfalkvidd]

@alowhum said in STM32?:

Really? On the Arduino nano I'm always connecting it to pin 2. It says to do so in the guide?

Well the guide also says "The IRQ is currently not used by the MySensors library so it can be left un-connected."

[tekka]

@alowhum Perfect!

[PhracturedBlue]

FYI, I didn't check the work done by tekka, but I didn't file a pull request for my 'sleep' code. I have support for using low power mode (reduce current from ~40mA to 4mA during sleep) but I had issues with reliable wakeup, so I've just switched my code to all using delay loops.

Initially I was using these boards for my sensors, but there is very little benefit compared to a 3.,3V pro-mini for my usage cases, and the power is 10x more when running (and 100x more when idle without my sleep patches that don't work)

I don't have any sensors that need the extra horsepower of the STM32 personally. The one benefit I did realize is having a USB serial port which removes the need for USB->TTL.

[freynder]

Exactly what I was looking for, thank you!

I can't seem to get it to work though. I'll report my findings here in case it helps:

Platforms tested: platformio and arduino ide, I mainly use platformio
Hardware: blue pill with RFM69HW connected like this:
NSS <-> PA4
MOSI <-> PA7
MISO <-> PA6
SCK <-> PA5
DIO0 <-> PA3

Issues encountered:

1. undeclared values while compiling. I used the following workaround:

// Workaround for STM32 support
#define ADC_CR2_TSVREFE  (1 << 23) // from libopencm3
#define digitalPinToInterrupt(x) (x)

2. examples/SecurityPersonalizer does not seem to work. I use it to write the AES encryption key to EEPROM. However, I do not see any output when running the sketch. As a workaround I created a minimal sketch to write the key to EEPROM which seemed to work.
   Update: Looks like I was using an old sketch. Works correctly with updated sketch.

3. stm32 sensor is unable to connect to gateway:

22898 TSM:FAIL:RE-INIT
22898 TSM:INIT
22900 TSM:INIT:TSP OK
22901 TSM:FPAR
24120 TSF:MSG:SEND,255-255-255-255,s=255,c=3,t=7,pt=0,l=0,sg=0,ft=0,st=OK:
26121 !TSM:FPAR:NO REPLY

[freynder]

@freynder said in STM32?:

stm32 sensor is unable to connect to gateway:

After further testing, this seems to work now. I'm not exactly sure why unfortunately. I'm now using the new RFM69 library. I noticed that communication seems to fail after uploading the sketch over stlink, even when clicking the reset button. When disconnecting/reconnecting the usb power all works well. Maybe that was the issue previously as well.

[freynder]

@PhracturedBlue What hardware were you using? Did it include a power led and voltage regulator? According to http://www.stm32duino.com/viewtopic.php?f=3&t=658&start=40 it should be possible to put the Blue Pill in stop mode using 13µA while sleeping when eliminating these.

I'm also interested in using the blue pill for the included RTC to periodically send data (RSSI, battery level, etc). I understand that with the current MySensors API this is not supported. E.g. combining a 24 hour sleep with a light switch: when the light switch is triggered, the 24 hour sleep is interrupted and starts again from scratch, so it is impossible to combine external interrupts with time interrupts, unless I am missing something. I am hoping RTC alarms could provide a solution here.

[gohan]

@tekka do you think stm32 is sufficiently stable running mysensors or should I stick to the "old" pro mini for battery powered sensors? (Also considering the ota updates support)

[freynder]

@gohan There is no support yet for sleep, so battery powered out of the box will not work. I've been testing custom sleep function (STOP mode, external interrupts) and so far was able to run a blue pill + RFM69 with MySensors between 0.01 and 0.20 mA (inconsistent results, not sure yet why). A sketch with just blue pill ran consistently at 0.01 mA. Unfortunately my multimeter does not allow more accurate measurements.

[tekka]

@gohan As @freynder pointed out, sleeping and low power modes are currently not implemented - if you do not need the higher speed & additional features that come along with the stm32 I'd stick (for the moment) to at328p for battery-powered sensors.