Using the SAMD51 True Random Number Generator @weasdown @MicrochipMakes

William Easdown investigates using the True Random Number Generator (TRNG) in the Microchip SAMD51 microcontroller:

Lately, I’ve been wanting to learn how to do direct register access on the SAM family of microcontrollers. I have a SAMD51-based Adafruit Feather M4 Express board, so was looking through the SAMD51’s datasheet to work out which registers I could do something useful with while not having to dive too deep into the microcontroller.

Looking down the extensive list of peripherals, I came across the True Random Number Generator (TRNG). This seems to be a relatively rare feature for a microcontroller – I haven’t seen any others with one – and it struck me that it should be fairly simple to get going because it shouldn’t need to interface with too many other peripherals or central parts of the chip.

Indeed, reading its description revealed it just need a clock source from the Main Clock (MCLK) and an interrupt setting up and I’d be ready to go. This involved setting three registers in total: the first to send the MCLK to the TRNG, the second to enable the TRNG and the third to enable interrupts from the TRNG when a new random number is available.

The SAMD51 datasheet states that the TRNG “passes the American NIST Special Publication 800-22 and Diehard Random Tests Suites”. William uses Arduino code to test the TRNG and a Python program to generate the results in the plot below.

You can read the details in the blog post here.

Adafruit publishes a wide range of writing and video content, including interviews and reporting on the maker market and the wider technology world. Our standards page is intended as a guide to best practices that Adafruit uses, as well as an outline of the ethical standards Adafruit aspires to. While Adafruit is not an independent journalistic institution, Adafruit strives to be a fair, informative, and positive voice within the community – check it out here:

Join Adafruit on Mastodon

Adafruit is on Mastodon, join in!

Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.

Have an amazing project to share? The Electronics Show and Tell is every Wednesday at 7pm ET! To join, head over to YouTube and check out the show’s live chat – we’ll post the link there.

Join us every Wednesday night at 8pm ET for Ask an Engineer!

Join over 36,000+ makers on Adafruit’s Discord channels and be part of the community!

CircuitPython – The easiest way to program microcontrollers –

Maker Business — “Packaging” chips in the US

Wearables — Enclosures help fight body humidity in costumes

Electronics — Transformers: More than meets the eye!

Python for Microcontrollers — Python on Microcontrollers Newsletter: Silicon Labs introduces CircuitPython support, and more! #CircuitPython #Python #micropython @ThePSF @Raspberry_Pi

Adafruit IoT Monthly — Guardian Robot, Weather-wise Umbrella Stand, and more!

Microsoft MakeCode — MakeCode Thank You!

EYE on NPI — Maxim’s Himalaya uSLIC Step-Down Power Module #EyeOnNPI @maximintegrated @digikey

New Products – Adafruit Industries – Makers, hackers, artists, designers and engineers! — #NewProds 7/19/23 Feat. Adafruit Matrix Portal S3 CircuitPython Powered Internet Display!

Get the only spam-free daily newsletter about wearables, running a "maker business", electronic tips and more! Subscribe at !

No Comments

No comments yet.

Sorry, the comment form is closed at this time.