#345 ESP32 vs STM32: Which one is better (Bluepill)?

many commenters tell me that the stm32 mcus are great the last time they were used on this channel was in video number 11 on july 27 2015 high time for a closer look crazy youtubers here is the guy with a swiss accent with a new episode and fresh ideas around sensors and microcontrollers remember if you subscribe you will always sit in the first row in video number 340 we discovered that the adcs of the esp8266 and esp32 are not excellent there viewers suggested that the stm32 is much better in this respect they should also be better in interrupt handling than the esp32 is this true and how about speed in this video we will check the typical stm32 boards we get on the usual platforms have a look on how to program stm32 boards with the arduino ide compare the features of the small stm32 boards with the esp32 in other videos i compared the esp32 with the esp8266 and the esp8266 with the arduinos check out the adc and compare it with the results in video number 340. check out interrupts and compare it with the esp32 check the speed as in video number 11 and see which one is faster in the end we should be able to see which mcu is best used for which project we have to thank roger clark for his outstanding work to integrate the stm32 line of mcu's into the arduino ide and the chinese manufacturers to produce extremely cheap ports stm recently joined the bandwagon and released their own arduino integration which is good news for makers unfortunately it did not work with my mappleboard so i went with roger's method but i leave your link in the description if makers talk about stm32 boards you usually hear blue pill i do not know how this relates to the well-known other blue pills maybe somebody knows another board looks similar and is an ancestor of the blue pill the maple mini the differences between the two are mainly a circuit to enable usb uploading i'm not sure if this is still needed today the form factor and the mcu are very similar by the way stm sells a whole range of stm32 chips the new arduino ide integration seems to support most of them so you are free to choose the chip you need for your project the maple and the blue pill use mainstream chips another pill the black pill uses an f4 chip which belongs to the high performance family for general purpose it is probably best to go with a blue pill in this video i will use the maple mini because my blue and black pills are still in the mail so what are the capabilities of these cheap boards compared with the esp32 both use 32-bit processors but not the same architecture the most significant difference is the lack of wi-fi and bluetooth if it matters for your project the next difference is the number of processors and the size of the flash and ram also the clock speed of the stm32 chips used in the blue pills is lower than the one of the esp32 both offer vast connectivity like multiple uarts i square cs and spi busses both are much much more capable than an ordinary arduino nano so it is already clear the hardware bang for the buck is very high for both boards compared with an arduino nano for example after the hardware we have to deal with software most of us already installed esp8266 or esp32 support in the arduino ide installing the stm32 support is not different enter this string in the preferences tab go to boards manager and search for stm32 and install at least the stm32f1x exports done now you can select the stm32f103c or some other series as said before the new arduino integration offers support for many more boards but how do we upload the sketch to the stm32 there we have three options the first is to use an ftdi adapter make sure you have one with 3.3 volts not only on the vcc pin but also on the data pins like this one the advantage is that you can use it also for serial debugging but you have to juggle with these jumpers not very comfortable and you have to use serial one instead of serial in your sketches the next option is the st-link for uploading to the blue pill this is probably the most comfortable choice because you do not need to change any jumpers and the upload speed is very fast but if you want to use serial you have to add an ftdi adapter to one of the three serial connections and use serial 1 serial 2 or serial 3 according to the pins you connected the ftdi adapter the third possibility is the one most compatible with the arduino or the esp32 you install a bootloader on the stm32 board using the sdm flash loader to do that successfully you have to download and install the flasher from the stm home page and this bootloader bin file for the maple and that one for the blue pill now you have to wire the boot 1 pin to ground and boot 0 to vcc and connect an ftdi adapter to the serial one pins on the blue pill there are chompers for that for the maple mini you have to use dupont wires after the start of the flasher you can select the com port of the ftdi adapter and click through the menus select the bin file from before make sure you allow pin files to show up and hit next now the bootloader is uploaded to the board remove first the boot jumpers and only afterwards the power otherwise you have to redo the whole procedure again the last step is to download and start install underscore drivers.bat as an administrator when you plug the usb plug into the stm32 board it should show up either as a dfu device or as a serial device called maple now it is ready to program if your device shows up as a dfu device the selection of the port is not essential only if it shows up as maple serial you have to select its port if you select maple mini the bootloader is automatically selected if you use the generic stm f103 board you have to check that the bootloader is selected now you can upload like with an arduino it works with a maple and should also work with blue pills maybe somebody can share his experience the infrastructure is now ready and we can start our tests first we make a comparison of the adcs to see if we find the differences between the stm32 and the esp32 mentioned by the viewers the stm32 needs one microsecond for one reading the esp32 is six times faster but as we know from video number 340 this advantage is paid by a lousy stability if we connect analog pin 0 to a 2.5 volts reference we also see variations and outliers as with the esp32 but they are much smaller if we use a moving average across 100 values we get a much smoother line as with the esp32 with this averaging we get two stable digits with the esp-32 with the stm32 we get three so the stm32 is about 10 times more stable let's check the offset error when i ground the analog pin we get precisely zero very good and at one volt the voltmeter and the stm32 values are very close not like the esp32 which displayed 0.91 volts and what about the problem of the arduinos when vcc changes the stm32 has an internal reference but i do not know if it is used for the adc because it runs on 3.3 volts it has an ldo to reduce the voltage from 5 to 3.3 volts which stabilizes vcc of the chip so a change on the 5 volt rail does not hurt the adc precision same as the esp32 and much better than the arduinos all in all viewers were right the stm32 clearly has much better adcs it is not as good as the external ads-1115 but to check battery voltage or to read an analog sensor it is good enough the next problem of the esp32 was the slow reaction on interrupts in video number 328 it needed more than three microseconds to react to an interrupt signal how does the sdm32 compare we use a similar sketch as with the esp32 but because the stm32 does not have two cores and does not run rtos we do not need the precautions of the esp32 we just toggle the pin as soon as the interrupt subroutine is called here the latency is only 1.3 microseconds around three times faster than the esp32 also not extremely fast but definitely much faster than the esp32 by the way if you want to know more about interrupts i strongly suggest watching video number three to eight also here the clear winner is the stm32 now we will check the speed as we did in video number eleven i used the same sketch used back then to be comparable and out of nostalgia ready go this was a fast race the two 30-bit racers went extremely fast while the older 8-biters are still on the track the first test is around input output operations and integer arithmetics already then i tested the maple mini interestingly it was faster back then the result was 609 milliseconds and today it is 735 for 10 000 loops it seems that the compiler changed from 2015. fortunately we have flags for compiler optimization if we use the fastest option we get 658 which is nearly as fast as back then in 2015 the esp32 did not exist so we test it now it performs with 596 which is faster than the stm32 the 735 or 658 of the stm32 can directly be compared with the 596 of the esp32 now let's compare floating point calculations the esp32 needs 356 milliseconds the stm32 1534 respectively 1359 with optimization switched on the esp32 is four times faster probably because it has a floating point processor definitely the esp32 is much faster than the stm32 and if we need it we still have the second core a deciding factor we did not talk about is the libraries the standard arduinos still have the biggest choice of libraries they usually are my fallback if i do not find a library for the esp32 nor the esp8266 both esp mcu's got good library coverage over the last years the stm32 in the arduino environment probably has less traction than the esps and unfortunately roger deleted most of his valuable stm32 posts on his blog so google pointed me quite often to non-existing links so stick to the wikis and a discord channel if you search for information i leave the links in the description i do not have a lot of experience with the availability of stm32 libraries maybe you can help out in the comments and tell the others where you had problems finding a library next pricing a blue pill costs around 3.50 including shipping the maple mini 4.30 and the esp32 mini my favorite for projects costs around 5.10 so we have a lot of facts together to summarize and see which mcu to use for which project the first question is always do we need wi-fi or bluetooth if so the esp32 is the right choice in principle you can add an esp-01 or a bluetooth port to an stm32 project to get connectivity but this is probably the exception if you need useful adcs or fast interrupt handling the stm32 definitely is the better choice and if every penny counts too a next question is do we need fast floating point arithmetic this can be for example for fast fourier transformation then the right choice is the esp32 in all other cases the choice is open this is when i look into my storage bins and decide which is the mcu i most probably will no more need in the future this is the right choice for those situations as always you find the relevant links in the description i hope this video was useful or at least interesting for you if true please consider supporting the channel to secure its future existence thank you bye

Channel: Andreas Spiess

Views: 154,386

Rating: 4.9423046 out of 5

Keywords: arduino, arduino project, beginners, diy, do-it-yourself, eevblog, electronics, esp32, esp32 datasheet, esp32 project, esp32 tutorial, esp32 weather station, esp8266, esp8266 datasheet, esp8266 project, greatscott, guide, hack, hobby, how to, iot, lorawan, nodemcu, project, simple, smart home, ttgo, wemos, wifi, stm32, bluepill, blackpill, Arduino IDE, nucleo, stm32f103c8t6, stm32f103, programming tutorial, tutorial, How-to

Id: boF4cX338k4

Length: 15min 37sec (937 seconds)

Published: Sun Jul 19 2020