Added STM32F407 board

_board/stm32f407vg_discovery.md

@@ -0,0 +1,23 @@
+---
+layout: download
+board_id: "stm32f407vg_discovery"
+title: "STM32F407 Discovery kit Download"
+name: "STM32F407 Discovery kit"
+manufacturer: "ST"
+board_url: "https://www.st.com/en/evaluation-tools/stm32f4discovery.html"
+board_image: "stm32f407.jpg"
+features:
+  - Microphone
+  - Audio Amplifier
+---
+
+The STM32F4DISCOVERY kit leverages the capabilities of the STM32F407 high performance microcontrollers, to allow users to easily develop applications featuring audio.
+
+It includes an ST-LINK embedded debug tool, one ST-MEMS digital accelerometer, a digital microphone, one audio DAC with integrated class D speaker driver, LEDs, push-buttons and an USB OTG micro-AB connector.
+
+## Purchase
+* [ST](https://www.st.com/en/evaluation-tools/stm32f4discovery.html)
+
+## Contribute
+
+Have some info to add for this board? Edit the source for this page [here](https://github.com/adafruit/circuitpython-org/edit/master/_board/{{ page.board_id }}.md).