3.x vs 4.x 4.1 4.1 pads unlabeled 7.84 44.1 khz 44.117khz 1280 x 400 adc audio audio lib oscillator audio noise guitar azeron bldc controller cli cn0391 teensy3.6 spi current dma dsp encoder display eeprom encoder footprint frank-b frank b host port i2c touchscreen keyboard max7219 7-segment midi midi out multi emf sensors noise nrf24l01 oled i2c teensy4 pcm1808 pdb pins power ppm processing psram radio rfi schematic serial smart matrix shield solved spi seperate synthesizer synth matrix midi t4.1 teensy teensy3.2 teensy 3.6 gpio ports teensy 3.6 usb host teensy4 dma spi teensy 4.0 teensy 4.0 ili9341 ra8875 teensy 4.1 teensy 4.x teensyduino teensy emulator midi vga teensy mpu6050 i2c teensy rtc tft thinpot timelib time syncing touchscreenusb x y usbhost_t36 web server hangs windows10iot