The STM32 is the third ARM family by STMicroelectronics. It follows their earlier STR9 family based on the ARM9E core, and STR7 family based on the ARM7TDMI core.

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SPI Interrupt Handler delay in STM32F303?

I'm working with an STM32F303 microcontroller configured in slave mode running at 72 MHz, and I've come across some strange behavior that I'm trying to track the origin of. The master first sends ...
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30 views

How to flash protected STM8/STM32 MCU?

I would like to flash a new firmware on my STM8L15xC8. I have ST Visual Programmer (STVP) installed and can successfully flash the MCU of the STM8 Discovery board. Now, I setup the STM8 Discovery ...
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37 views

STM32F2xx: Data from SPI Slave to Master

I have a STM32F2xx connected to a FTDI UM232H using SPI, STM32F2xx will be configured as SLAVE and FTDI will be configured as MASTER My scenario is this, I am getting data in STM32F2xx, and when I ...
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2answers
90 views

Understanding SPI

I have some problems understanding SPI: I am currently using STMF2xx to connect with FTDI UM232H, I will configure my STMF2xx into slave and FTDI into master. But, I am having problem getting the ...
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54 views

RTC DS1307 3.3V I2C and Oscilloscope impedance

I'm working on a library for STM32 to learn I2C protocol (Software I2C, not hardware). I connect my DS1307 (Sparkfun BOB-12708) : (Here is the module schematic) : I remove welding on the SJ2 jumper ...
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103 views

STM32F103, Having trouble nesting interrupts

I'm trying to interrupt into a USART handler from inside an RTC_Alarm handler, but it doesn't work. I have set the NVIC: ...
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48 views

STM32F030 RTC wakeup from stop mode

I'm writing an app, that most of its time will spend in STOP or STANDBY mode (battery powered microsystem). I'd like the internal RTC to wakeup my STM32 every 5 minutes, enter the ISR, do its tasks in ...
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1answer
93 views

Why does my MCU go back? (to the previous instruction)

I don't know why but I see the same odd behaviour sometimes in the debugger environment. Look at this code (function): ...
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1answer
76 views

Full duplex SPI Master using DMA - STM32F105

I'm trying to write a SPI driver for an STM32F105, using DMA functionality. I'm using ST's Standard Peripheral Library. I'm not using interrupts. I can talk to the destination device if I use standard ...
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1answer
70 views

STM32F10x SPI - No Clock

I'm trying to get basic SPI operation working on an STM32F107VC chip using the WaveShare Port107 development board. I'm trying to initialise SPI1 which resides on PA4-PA7. I'm attempting a simple ...
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2answers
68 views

STM32F103 - TIM5 doesn't exist on medium density devices ? How do I tell what else is missing?

I've tried setting TIM5 as a timebase timer with an interrupt, when the compiler gave me the following error: 39: error: 'TIM5_IRQn' undeclared (first use in this function) Than I though I'll ...
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1answer
76 views

STM32F1 troubles with a timer

I'm having some troubles with setting up a 1 second timer on STM32F103 mcu. I have set Timer 2 to have a prescaler of 1099 and a period of 65514, so I'm expecting to have a 1 second interrupt rate: ...
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1answer
72 views

PDM to PCM conversion workload on 32-bit micro (such as STM32)

Can anyone provide a rough estimate of the processing power required to do PDM (e.g. audio from MEMS microphone) to PCM conversion on a 32-bit microcontroller ? Specifically - I see ST provides a PDM ...
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65 views

SPI TX Error on STM32F4xx

I have tried posting this question on the ST forums but have not seen any traffic on it so I figured I would try here. Background STM32F407IGT processors SPI2 peripheral being serviced by DMA ...
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1answer
40 views

What's the concept of these three options for configuring the memory of STM32?

I have read the STM32F10x Reference manual but a section about "Reading the Flash memory" is not clear to me, yet. I mean this part(page 59): I have several question: What's the Latency? in fact ...
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3answers
80 views

What is SPI Interrupt (SPIE) in SPI control register?

I have been trying to understand SPI Interrupt i.e. what does it do and why is it used ? Reading about it on the web has not helped me. Can some one please explain it in a simple terms ?
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1answer
74 views

Unable to read file greater than 2K in FatFS

I am reading a file from the SPI Flash with FATFS file system, on STM32F103 platform running FreeRTOS. I can successfully read File of size less the 2048, but if read a file file of size greater than ...
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70 views

STM32 ADC sampling problem

I'm using the STM32F2 microcontroller, and have a weird problem with the ADC. Seems like the ADC sampling circuit needs a reset to take a sample, as the ADC value quickly drops after the reset. For ...
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1answer
105 views

USB interface with STM32

I'm experimenting with native USB in STM32. I've not found any "step by step", or a little more well structured tutorial, how to implement CDC or mass storage for example. I've found some examples, ...
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71 views

STM32F2 code execution problem -solved

I just got into using STM32F2 microcontrollers. However, I am unable to get the micro work. I have a board designed by my own, with only the microcontroller, power supply capacitors, 2 leds and a UART ...
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1answer
110 views

STM32F103 simple countdown timer (with no interrupts)

I'm trying to create a simple countdown timer (without using interrupts) - to use to check for timeout while waiting for an external event to occur. Ideally, I'd like to preload a timer counter with ...
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1answer
60 views

STM32F4xx input pin reads wrong state on first run but not subsequent

I am working on a program which reads the state of a pin at startup to determine an operational mode. When I run the code on first power up, it reads incorrectly, but subsequent resets without power ...
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1answer
56 views

STM32F102 USB Programming

I am currently designing a board for a STM32F102 chip which needs to be able to use the USB bus to transfer data while the chip is running. However I also want to be able to program the chip through ...
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31 views

Eclipse Template for STM32L

Where can I find additional templates for the ARM-GDB debugger for eclipse? Otherwise, how do I create a template and which variables would change from the STM32F series and the L series? Thanks
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1answer
117 views

STM32F103 Systick Interrupt stopped working when debugging in ram - (Coocox IDE)

I tried debugging my code in ram in order to increase the flash's life (only rated at 10k writes minimum) Anyways, I have tied the boot0 and boot1 pins to 3.3v and set the compiler to debug from ram ...
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2answers
171 views

Independent watchdog (IWDG) or Window watchdog (WWDG)?

I'm still searching to find an answer for this question: Why while the stm32 MCUs have a perfect watchdog (I mean Window watchdog (WWDG)), there is a simple watchdog (Independent watchdog (IWDG)) ? ...
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99 views

STM32F103 strange behavior

I'm working with an STM32F103 device and am experiencing some strange behavior that I'm not so sure about where start with when it comes to debugging it. I previously asked a question regarding DMA ...
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1answer
45 views

The same flag for an interrupt

I think I'm mixed up a bit in NVIC of stm32 MCUs. I took a look in the SPI.h of the STM32F10x standard peripheral library. I don't know that why while there is ...
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47 views

USB in Nucleo F302R8

I'm using the Nucleo F302R8 to build the firmware for a new board I'll develop using the same MCU. I'm trying to use USB CDC to have a VCP. I've started with CubeMX with the Nucleo F302R8 template, ...
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1answer
124 views

STM32F1 Can't I use the internal voltage reference as the ADC reference?

There seems to be a badgap voltage reference built-in in the STM32F1 microcontrollers (on ADCx_IN17). Coming from AVRs it seems to me very strange that it's not possible to use this reference as the ...
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1answer
121 views

What USB class should I implement?

I'm playing around with STM32F4 Discovery board and libopencm3. I want to send data acquired from ADC channels over usb and display some charts on the computer. After doing some research on USB class ...
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2answers
249 views

SPI1 doesn't work

I'm working on a simple project. I want to send a string. the string is "Rohalamin". the second board after recieve the string should turn on the LED. the program for first board is (the MCU for ...
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1answer
115 views

jpeg images in STM32 internal flash

I'm using both STM32F103 and STM32F407 with a SEPS525 SPI driven OLED display (160x128). I want to store images to display in internal flash, but BMP uncompressed images with 16bit colors are huge ...
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67 views

GPIO control of alternate function pin

I have an STM32F4discovery and using a pin as SPI CLK. But I also want to be able to control the pin as GPIO to generate ANY frequency I want (STM32 only lets you prescale APB clock). How can I ...
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1answer
143 views

Is it possible to program an STM32 with an Arduino?

I have one of these: http://www.ebay.com/itm/111297094334?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649 I know an USB-TLL dongle is usually used to program it, but I don't have one and I ...
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38 views

Parallel Write On External Clock on STM32

I am using 8 GPIO pins on an STM32F407 for a parallel write to an external device (FT232H). The parallel write is synchronous, ie. I have to synchronize my data to a clock provided. According to the ...
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2answers
87 views

STM32F3 Discovery 5V output

I want to use a STM32F3 GPIO (3.6V) to drive another device using 5V input. Which is the correct way to do so? I know that is possible to use the open drain mode on the GPIO, but I'm not sure if I ...
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154 views

STM32 RTC alarm not configuring for the second time

I am using STM32l151vbt6 MCU and I am trying to configure RTC Alarm for every 15th minute. (That is 0, 15, 30 and 45th minute of the every hour.) I can configure the alarm and it will work for the ...
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1answer
93 views

Why does `RCC_GetClocksFreq` return different results than I expect?

I have a STM32F427 MCU with a 8MHz HSE crystal. I am setting up the clock as follows: ...
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5answers
242 views

How is time of supplied real time clock module maintained without battery?

I am thinking about purchasing this RTC ( real time clock ) module. Since this particular item comes supplied without a battery, I wonder how the time is being kept running in the chip since it's ...
0
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1answer
71 views

STM32 not booting without J-link

I've got a device with STM32F439 microcontroller on it. I flashed the firmware using the J-Flash utitilty (flashed and read back data is same). Then started the application from J-flash: everyting ...
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1answer
227 views

stm32f10x: how to redirect timer output to a given GPIO pin

I would like to programmably send pwm signal to one of the 16 output pins. One way to do this is to trigger interrupt on timer reload and on output comare event, and then to update the corresponding ...
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83 views

STM32 FSMC Timing Computation

I'm working on FSMC protocol of STM32 micro controller The formula for calculate FSMC timing is below, but I have a hard time understanding it. From ST Application Note Can someone walk be ...
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170 views

STM32 Timer Outputting Clock on GPIO without using PWM or Interrupts

I'm trying to output a fast clock, 90kHz on an I/O using the 32F0308DISCOVERY board by using the OC_Toggle mode for TIM3, ...
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2answers
171 views

STM32 SPI w/ DMA “BUSY” flag set

My software appears to be working as expected, but the BSY flag is not clearing in the SPI register. Background: I am trying to get SPI working with DMA on the STM32. After figuring out that the DMA ...
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115 views

STM32 Timer Internal Clock Source

As I understand, the internal timer clock source on the STM32(F4) microcontrollers can be either APB1 or APB2. However, I can't find which timers get which clock. I already found ST AN4013, which ...
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85 views

Simulate STM32F4 brownout reset using STM32F100

The STM32F4 MCU has a brownout reset feature. According to the manual, section 5.2.2, when the supply voltage VDD drops below the selected VBOR threshould, a device reset is generated. After reset, I ...
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1answer
125 views

Look up tables, Flash or SRAM?

A STM32F4 platform is used, which has 192kBytes SRAM, which is sufficient for me. I am trying to build a look up table. The LUT will be used in calculation several times. And I want to put it in SRAM ...
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1answer
497 views

Stm32 Event and interrupts

I started studying interrupts on stm32 specifically the stm32f4 discovery board. i found this example in which you have to press the button to start the interrupt and push it again to stop it. In ...
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1answer
87 views

How does a stm32f chip set its GPIO speed? (hardware, not register setting)

The speed of GPIO of a stm32 chip is set by register of OSPEEDR. It shows: 00: Low speed 01: Medium speed 10: Fast speed (50MHz in library) 11: High speed (100MHz in library) My guess is ...