With the AVR-based Arduino boards, doing an input capture in a timer/counter (to time stamp a signal edge) was very simple, although not supported in the Arduino library. It’s just three instructions to completely configure. With the SAMD21 it becomes a major programming effort to get an external signal to the timer/counter. So 14 instructions. …
The Arduino documentation states that the maximum resolution of the PWM analogWrite (not the DAC analogWrite) is 12 bits. However the SAMD21 has 16-bit timer/counters and the actual resolution is 16 bits. So you can call analogWriteResolution(16) successfully. Because of the high resolution, the PWM frequency is a fairly low 732Hz, being 48MHz/65536. If the …
The SAMD21 microcontroller in the more recent Arduino board designs had a clock/calendar built-in. It’s one of the operating modes of the Real-Time Counter. There are counter fields fields for seconds, minutes, hours, (optional AM/PM), days, months, and years. However the year field is only 6 bits, allowing for only 64 years starting at a …
I’ve neglected blogging because I really don’t have any progress to show. I’ve been dealing with sketchy and possibly wrong documentation so have been tediously testing out each feature figuring out exactly what is needed and what is not needed to get things to work. The net result should be that the next book (on …
A friend of mine, David Sparks, is using a SAMD based board (a Seeedstudio XIAO) to be a real time clock. You can see his project here: https://github.com/IowaDave/SAMD21-RTC-Clock. The SAMD has a Real Time Counter which can be configured as a Real Time Clock (RTC=RTC!) eliminating the need for a second component. However when run …
The SAMD21 has 7 clock sources. Each clock source can drive one or more of the nine Generic Clock Generators. The generic clock generators have a programmable clock divider, and each of the 37 peripheral clocks can be fed from one of the clock generators. This is a somewhat formidable mess. The Arduino boards that …
I’ve touted the Arduino Nano Every and the Arduino Nano 33 IoT as the two best buys in the Arduino lineup, and that they should be preferred when appropriate to the application. But why are these such good deals? First, they are both in the “Nano” form factor. This smaller board is less expensive to …
As I’ve been going far inside the SAMD21 Arduino boards, I’ve realized the main distinction of the ARM-core SAMD21 compared to the AVR architecture ATMega microcontrollers, and indeed to other microcontrollers I’ve used in the past. The ARM-core microcontrollers are actually a two part design. There is the ARM designed processor core, and the vendor …
Like most of the AVR-based Arduino boards, there is a bootloader program resident on the SAMD boards (Arduino Zero, Arduino Nano 33 IoT, and the Arduino MKR series) to handle the loading of programs (AKA “Scripts”) via the USB-serial port. This program can erase and write into the Flash ROM in the microcontroller, and start …
Catchy title, and the answer is certainly “yes” because of generally better price/performance and that people like newer designs. But let’s back off a little. Currently the lowest price genuine Arduino (not clone) board is the Arduino Nano Every. It’s less than half the price of the traditional Arduino Uno, and can replace the Uno …