purposes location parallelism modularity interference wired UART, USART, SERCOM, PIO, bit-bang asynchronous serial RS-232, RS-422, RS-485 serial broadcast ATtiny412 ATtiny45 components video hello.bus.45.bridge board traces traces+exterior interior hello.bus.45.node board traces traces+exterior interior hello.bus.45.c makefile hop-count chip LED strip hello.hop-LED.t1624 board components top interior hello.hop-LED.t1624.ino hello.hop-LED.py video broad-hop hello.broadhop-LED.t1624 board components top interior hello.broadhop-LED.t1624.ino hello.broadhop-LED.py video hello.broadhop-serial.D11C board components top bottom holes interior synchronous serial SPI SDI/SDO/CS/SCK, PICO/POCI,MISO/MOSI/SSlibrary library SD memory cards specification FAT hello.uSD.RP2040 board components top bottom holes interior hello.uSD.RP2040.py video hello.uSD.D11C board components traces traces+exterior interior hello.uSD.D11C.ino video hello.uSD.44 board components traces traces+exterior interior hello.uSD.44.read.c make output I2C, TWI SCL/SDA, pull-ups Qwiic STEMMA library library hardware software hello.I2C.t1614 board components traces traces+exterior interior hello.I2C.ino video ATtiny412 I3C asynchronous unclocked ATP hello.ATP.RP2040 board components traces interior send receive timing video USB TinyUSB CircuitPython HID MIDI Arduino HID MIDI Ethernet chip module CAN, LIN MODBUS DMX wireless radios oscillator, mixer, PA, LNA, IF, I/Q, demod, baseband, filters antennas Q, antenna gain, impedance matching, short antennas FabFi single-chip ESP32 (2.4 GHz Wi-Fi, Bluetooth, 32-bit) versions ESP32-C3 module hello.button-blink.C3 board components traces interior hello.Web-blink.C3.py microdot.py microdot_asyncio.py video hello.BLE-blink.C3.py blueart.py hello.BLE-blink.C3.html video NUS Web Bluetooth ESP32-WROOM pins hello.ESP32-WROOM board components traces traces+exterior holes interior Web client video Web server video UDP video Bluetooth serial video 802.11 LR ESP32-CAM hello.ESP32-CAM board components traces traces+exterior holes interior camera video ESP8266 (2.4 GHz Wi-Fi, 8-bit) chip module board power hello.ESP-01 board components traces traces+exterior holes interior Web server video hello.ESP-WROOM-02D board components traces traces+exterior holes interior Access point video MFRC522 (13.56 MHz RFID) chip module library security hello.MFRC522.t1614 board components traces traces+exterior interior video nRF24L01+ (2.4 GHz ISM) chip module library project antennas hello.nRF24L01P.44 board components traces traces+exterior interior nRF905 (433/868/915 MHz ISM) chip module library RN4871 (2.4 GHz Bluetooth) chip module commands hello.RN4871.ftdi board components traces traces+exterior interior video CC2541 (2.4 GHz Bluetooth) chip HC-08 HM-10 HM-11 commands hello.HM-11.ftdi board components traces traces+exterior interior video nRF52 (2.4 GHz Bluetooth, ISM) chip module project project CYW43438 (2.4 GHz, Wi-Fi, Bluetooth, FM) chip module board RFM95/6/7/8 (433/470/868/915 MHz LoRa) chip module LoRaWAN SX1276 (137-1050 MHz LoRa) chip board ExpressLRS SIM800L (GSM) module software radio OpenWrt OSI layers 7: application (HTTP) 6: presentation (SSL) 5: session (RPC) 4: transport (TCP, UDP) 3: network (IP) 2: data link (MAC) 1: physical (PHY) physical media capacity bandwidth * log_2 (signal/noise) wired single-ended, differential, powerline open collector, open drain transmission (pass) gate, tri-state transmission line waveguide SONET optical fiber wireless RF FCC Part 15 ISM 802.11 Wi-Fi sensing 802.15 ZigBee 6LoWPAN Bluetooth BLE GATT GAP UUID Services app stack optical transmitter receiver LiFi RGB acoustic modulation PCM: Pulse-Code Modulation PPM: Pulse-Position Modulation OOK: On-Off Keying FSK: Frequency-Shift Keying BPSK: Binary Phase-Shift Keying QAM: Quadrature Amplitude Modulation OFDM: Orthogonal Frequency-Division Multiplexing FHSS: Frequency-Hopping Spread Spectrum DSSS: Direct-Sequence Spread Spectrum UWB: Ultra-WideBand channel sharing ALOHA Master-Secondary Token Ring TDMA: Time-Division Multiple Access FDMA: Frequency-Divsion Multiple Access CSMA: Carrier-Sense Multiple Access CD: Collision Detection CA: Collision Avoidance 1-persistent: transmit when clear nonpersistent: random backoff p-persistent: probability to transmit CDMA: Code-Division Multiple Access MIMO: Multiple-Input Multiple-Output "PDMA": Physical-Division Multiple Access errors detection, correction block, convolution codes parity, checksum, Hamming, Reed-Solomon, Turbo networking Internet protocols RFCs example example IPv4, IPv6 unrouted, routed, unicast, multicast, broadcast addresses DNS DHCP NAT PAT private UDP, TCP HTTP BGP AODV ROLL sockets udpsnd.js udprcv.js video udpsnd.py udprcv.py udpsnd.c udprcv.c WebSockets Wireshark SLIP slattach route hello.bus.45.SLIP.c makefile udp_slip.py video IoT, event APA assignment individual assignment: design, build, and connect wired or wireless node(s) with network or bus addresses and local input &/or output device(s) group assignment: send a message between two projects