====== Core 32 STM32F4 ======

{{ :neonking:core_stm32f4.jpg?600 |}}

===== Introduction =====

==== Features ====

  * **1MB Flash and 192k RAM **
  * **Easily available** for private persons in small quantities and no SMD soldering skills required
  * ARM Cortex-M4 CPU is widely supported by the GNU toolchain, accordingly source code can be compiled under Windows/Linux/MacOS w/o spending money for an expensive ARM compiler
  * **Increased performance** compared to STM32F1xx and LPC17xx because of the higher frequency (168 MHz)
  * **Enhanced instruction set** with DSP operations makes Cortex-M4 very interesting for audio applications (e.g. Synths and Fx)
  * MIOS32 applications running more than 2..3 times faster than on STM32F103RE @72 MHz, and ca. 50% faster than on a LPC1769 @120 MHz
  * Very useful integrated peripherals for MIDI and Synthesizer applications, such as **UART, SPI, I2C, USB, CAN, Timers, ADC, DAC**
  * The USB OTG (Micro-USB) socket supports **MIDI Host**, which means that it's possible to connect a USB MIDI Keyboard or Synth 
  * **The on-board Audio DAC predestinates this module for synthesizer projects** - it could even be used standalone without the MBHP_CORE_STM32F4 breakout board for this purpose.
  * in distance to STM32F103RE, **CAN and USB can be used in parallel**
  * **It's easy to interface external components like SD Cards and MBHP_ETH**
  * STM32F4xx is supplied at 3V, but **5V tolerant inputs allow to access all existing MBHP modules without additional hardware**.
  * **Performance boost by using the DMA** for background operations, such as scanning DIN/DOUT modules, analog inputs but also I2S transfers (Audio Output) w/o loading the CPU
  * **Realtime Operating System: FreeRTOS**
  * **no external flash programmer required**, ST-LINK/V2 is part of the STM32F4DISCOVERY board to program the MIOS32 bootloader into a "virgin" device
  * **Fast upload of application code via USB MIDI** (ca. 50kb/s) - thanks to the MIOS32 Bootloader

===== Known Issues =====

  * **ADCs cannot be supplied at 5V**, 3.3V is the limit, and the STM32F4DISCOVERY board uses an even lower voltage (3V). This decreases the signal/noise ratio. The MBHP_AINSER64 and MBHP_AINSER8 module helps to overcome this by using an external 5V ADC.
  * **Pin mapping suboptimal in some cases**. E.g., the outputs of the integrated DAC (not the on-board Audio-DAC) overlay SPI1 pins. However, one DAC channel has been freed up with the small drawback that SPI1 can't be used in slave mode.
  * The IO pins of the SDIO peripheral (high speed SD Card access) conflicts with the on-board Audio DAC, so that it can't be used.
  * Although the chip contains 6 UARTs, **only 4 RX and TX pins could be found for MIDI IN/OUT**. IN3/OUT3 even have to use two different UARTs.
  * No on-board Ethernet PHY
  * **No PHY for the second USB peripheral** - would be nice to have, e.g. to support USB MIDI device and host (e.g. for the connection of a USB MIDI Keyboard), USB Memory Sticks or even a USB harddisk in parallel.

===== Parts List / Schematic=====

See [[stm32f4_core_board_parts_list|Core32 Parts List]]

  * {{http://ucapps.de/mbhp/mbhp_core_stm32f4.pdf|Core32 Schematic}} <sup>UCapps</sup>

===== Inputs/Outputs Ports =====

{{ :neonking:core32-architecture.jpg?800 |}}

===== Buy Places =====

  * [[http://www.digikey.com/product-detail/en/stmicroelectronics/STM32F407G-DISC1/497-16287-ND/5824404|Digikey]]
  * [[http://www.mouser.fr/ProductDetail/STMicroelectronics/STM32F4DISCOVERY/?qs=J2qbEwLrpCGdWLY96ibNeQ%3d%3d|Mouser]]
  * [[http://export.farnell.com/stmicroelectronics/stm32f407g-disc1/dev-board-foundation-line-mcu/dp/2506840?selectedCategoryId=&exaMfpn=true&categoryId=&searchRef=SearchLookAhead&searchView=table&iscrfnonsku=false|Farnell]]
  * [[https://www.amazon.com/STM32F4DISCOVERY-ST-STM32F407-Evaluation-Development/dp/B00CW9AKDY|Amazon]]
  * [[http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2047675.m570.l1313.TR2.TRC0.A0.H0.XSTM32F407.TRS0&_nkw=STM32F407&_sacat=0|Ebay]]
  * [[http://www.watterott.com/de/STM32F4Discovery|Watterot DE]]