Electronics project notes / Teensy notes

⚠ This is for beginners and very much by a beginner / hobbyist It's intended to get an intuitive overview for hobbyist needs. It may get you started, but to be able to do anything remotely clever, follow a proper course or read a good book. Some basics and reference: Volts, amps, energy, power · batteries · resistors · transistors · fuses · diodes · capacitors · inductors and transformers · ground Slightly less basic: amplifier notes · varistors · changing voltage · baluns · frequency generation · Transmission lines · skin effect And some more applied stuff: IO: Input and output pins · wired local IO · wired local-ish IO · ·  Various wireless · 802.11 (WiFi) · cell phone Sensors: General sensor notes, voltage and current sensing · Knobs and dials · Pressure sensing · Temperature sensing · humidity sensing · Light sensing · Movement sensing · Capacitive sensing · Touch screen notes Actuators: General actuator notes, circuit protection · Motors and servos · Solenoids Noise stuff: Stray signals and noise · sound-related noise names · electronic non-coupled noise names · electronic coupled noise · ground loop · strategies to avoid coupled noise · Sampling, reproduction, and transmission distortions Audio and video notes: See avnotes USB: everyday · power · connectors · lower level · misc Platform specific: : Microcontroller and computer platforms ·· Arduino and AVR notes · ESP series notes · STM32 series notes · Teensy series notes Less sorted: Ground · device voltage and impedance (+ audio-specific) · electricity and humans · Soldering · landline phones · pulse modulation · PLL · Multimeter notes · signal reflection · Project boxes · resource metering · Radio and SDR · vacuum tubes · Unsorted stuff · 'E-fuse' Some stuff I've messed with: Avrusb500v2 · GPS · Hilo GPRS · JY-MCU · DMX · Thermal printer · See also Category:Electronics.

See Electronics project notes/Microcontroller and computer platforms#Teensy for a general introduction.

RAM

The Teensy 4's 1024 KByte is split into two parts: (see also the memory map on the product page)

• RAM1

512KB

more tightly coupled. Code, static variables, and stack will be put here

• RAM2

512KB

runs slower than RAM1(verify)

but optimized for DMA

defining with DMAMEM puts things in RAM2

used for buffers, larger arrays, and dynamic allocations (the heap)

when using DMA, you would want to put it here so DMA can run in parallel with the CPU.

Look at the manual, "4.12 SRAM accesses".

These are accessed differently, and the teensy libraries will use some of this, so don't count on getting all of it, or storing one big array in there.

Teensy and USB

See

https://www.pjrc.com/teensy/

https://www.pjrc.com/teensy/techspecs.html