Recent content by LenSamuelson

Being Debian-based and given RaspberryPi.org's attention to standards compliance and accessibility, it almost certainly supports Linux-standard hot swap device nomenclature. I have several "serial" devices and use the system's default "/dev/serial/by-id/..." directory to name them. My...

For custom board developers: NXP longevity program Our current product depends on 150 MHz Kinetis K60 and K66 parts, and we would be in deep trouble if these devices become unavailable. Seeing the announcement of PJRC's last-device availability caused us to look into the question. We are...

Disabling/enabling interrupts instead of save/restore: subtly dangerous You make a good observation. The ATOMIC_BLOCK code (that I'm seeing for the first time so take this with a grain of salt and subject to further study) seems like a good solution, though it's a strict boolean...

If you are certain that your application is AC, any of the DACs will likely work of you. If you expect to do very low frequencies or DC, then the PT8211 becomes a good choice. The PT8211 is a straight-up 2-channel R2R DAC driven by I2S, and the high-pass output capacitors can be replaced with...

Preprocessor definitions require "#" character It looks like a "#" character is missing. The way to enable these things is with a preprocessor macro, so use "#define" preprocessor operator. #define AUDIO_PT8211_OVERSAMPLING #define AUDIO_PT8211_INTERPOLATION_LINEAR

I've been running experiments with PJRC PT8211 audio board (stereo I2S 16-bit DAC) replacing the output capacitors with shorting wires. It works beautifully. Good results from DC up to 500 ksamples/second. The results are good enough to allow us to move toward an affordable test bench for our...

We have been checking PT8211 behavior fairly closely over the last week. Connected using the PJRC standard board-on-board style... No real surprises on the noise front. Off topic... Has anyone verified that right/left channel signal outputs match the board's silkscreen labeling?

Bottom line question: Does anyone know of issues in driving DC-to-kHz signals with a Teensy audio shield? I've been involved in a multi-channel (64-channel) analog data acquisition project and want to propose a regression / system test platform to our management. We have had great success in...

PWM emphasizes pulse width not absolute clock accuracy I don't think I've ever seen a PWM-controlled device that places tight requirements on the accuracy of its clock rate. The two parameters that almost all PWM-driven devices use are carrier frequency and either duty cycle or pulse width...

Related to drive strength, seen in Raspberry Pi documentation Interesting coincidence... Reading some tech docs on the Raspberry Pi over the weekend, I discovered that's approximately how they handle PIO drive strength...

UART/DMA: unlikely to be worth the effort I have implemented DMA-based UART communication using Kinetis microcontrollers in the same family as the one in the Teensy3.5. The only reason we could justify the major investment of development time is due to our need to drive crazy high continuous...

I agree with chipaudette, our project has had noise issues and channel cross-talk issues using the 4 onboard ADCs in a K60 design. We are "getting along OK" but have discovered a need to take great care with the analog signal chain to avoid surprises that have taught us some hard lessons. If we...

Board flex is a known problem with BGA parts, maybe SparkFun could consider a thicker board design? I am unfamiliar with the physical specs on the MicroMod form factor. My work project had several failures of a 144-ball BGA mounted K60 part (similar to the K66 in the Teensy 3.6) in a very harsh...

equal priorities: round-robin scheduling First answer: The program as written has asked the the executive to run two threads with equal priority. Both threads ("tasks") are written to run continuously, so the apparent gap in execution of the loop() thread is the execution of the loopSec()...

Depends on legal / insurance answers If your target application has safety implications (a question you and your co-workers would need to answer), then the you can change the Big Decision into a few smaller ones: Are you willing to risk having Arduino software involved? If using Arduino...