{"id":24974861,"url":"https://github.com/atoomnetmarc/samd21-breakout","last_synced_at":"2026-01-08T04:41:37.977Z","repository":{"id":111232573,"uuid":"567823211","full_name":"atoomnetmarc/SAMD21-breakout","owner":"atoomnetmarc","description":"SAMD21 breakout board, layout inspired by Arduino MKR Zero.","archived":false,"fork":false,"pushed_at":"2022-12-09T20:35:50.000Z","size":1017,"stargazers_count":1,"open_issues_count":0,"forks_count":0,"subscribers_count":1,"default_branch":"main","last_synced_at":"2025-02-03T20:49:58.362Z","etag":null,"topics":["arduino-m0","arduino-mkr","atsamd21g18a","kicad","samd21"],"latest_commit_sha":null,"homepage":"","language":"HTML","has_issues":true,"has_wiki":null,"has_pages":null,"mirror_url":null,"source_name":null,"license":"apache-2.0","status":null,"scm":"git","pull_requests_enabled":true,"icon_url":"https://github.com/atoomnetmarc.png","metadata":{"files":{"readme":"README.md","changelog":null,"contributing":null,"funding":null,"license":"LICENSE","code_of_conduct":null,"threat_model":null,"audit":null,"citation":null,"codeowners":null,"security":null,"support":null,"governance":null,"roadmap":null,"authors":null,"dei":null,"publiccode":null,"codemeta":null}},"created_at":"2022-11-18T17:01:23.000Z","updated_at":"2025-01-24T11:54:23.000Z","dependencies_parsed_at":null,"dependency_job_id":"5c28dba6-b8b7-4003-b597-b81b09e643b3","html_url":"https://github.com/atoomnetmarc/SAMD21-breakout","commit_stats":null,"previous_names":[],"tags_count":0,"template":false,"template_full_name":null,"repository_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/atoomnetmarc%2FSAMD21-breakout","tags_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/atoomnetmarc%2FSAMD21-breakout/tags","releases_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/atoomnetmarc%2FSAMD21-breakout/releases","manifests_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/atoomnetmarc%2FSAMD21-breakout/manifests","owner_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners/atoomnetmarc","download_url":"https://codeload.github.com/atoomnetmarc/SAMD21-breakout/tar.gz/refs/heads/main","host":{"name":"GitHub","url":"https://github.com","kind":"github","repositories_count":246150458,"owners_count":20731419,"icon_url":"https://github.com/github.png","version":null,"created_at":"2022-05-30T11:31:42.601Z","updated_at":"2022-07-04T15:15:14.044Z","host_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub","repositories_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories","repository_names_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repository_names","owners_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners"}},"keywords":["arduino-m0","arduino-mkr","atsamd21g18a","kicad","samd21"],"created_at":"2025-02-03T20:43:01.605Z","updated_at":"2026-01-08T04:41:37.949Z","avatar_url":"https://github.com/atoomnetmarc.png","language":"HTML","funding_links":[],"categories":[],"sub_categories":[],"readme":"ATSAMD21G18A-AU breakout board with the physical layout inspired by the `Arduino MKR Zero`.\n\n![](SAMD21%20breakout.jpg)\n\n# Power supply\n\nSupply power to 3V3 pin. Or supply power to 5V pin (or USB) and get free 3V3.\n\n# Platformio\n\n`platformio.ini`:\n```ini\n[env:mzeroUSB]\nplatform = atmelsam\nboard = mzeroUSB\n```\n\n# Pinout\n\n| Arduino   | SAMD21    | Alternate |\n| --:       | --:       | --:       |\n| AREF      | PA03      |\n| A0        | PA01      | DAC\n| A1        | PB08      |\n| A2        | PB09      |\n| A3        | PA04      |\n| A4        | PA05      |\n| A5        | PB02      |\n| RX        | PA11      | D0\n| TX        | PA10      | D1\n| ~D2       | PA08      | SDA2\n| ~D3       | PA09      | SCL2\n| ~D4       | PA14      |\n| ~D5       | PA15      |\n| D6        | PA20      |\n| D7        | PA21      |\n| ~D8       | PA06      |\n| ~D9       | PA07      |\n| ~D10      | PA18      |\n| ~D11      | PA16      | SDA3\n| ~D12      | PA19      |\n| ~D13      | PA17      | SCL3\n| SDA       | PA22      |\n| SCL       | PA23      |\n| MISO      | PA12      |\n| MOSI      | PB10      |\n| SCK       | PB11      |\n\n# Soldering\n\nSolder every component except U1, J2, J4 and J5. Begin with all the components on the bottom.\n\nClean board.\n\nApply current limited (50mA) 5V to GND and 5V pin. Current should be about 6mA. Measure voltage on 3V3 pin, it should be 3.3V. Disconnect. Connect USB, both LEDs should light up again.\n\nSolder U1 carefully. Inspect U1 pins with microscope for shorts or missing soldered pins. Correct when found.\n\n![This SAMD21 needs some work](soldered%20samd21%20with%20problems.jpg)\n\nClean again. Inspect again.\n\nMeasure all adjacent signal pins (on headers J4 and J5) for shorts: XIN21, XOUT32, A0, AREF, GND, 3V3, A1, A2, A3, A4, ~D8, ~D9, ~D2, ~D3, TX, RX, 3V3, GND, MOSI, SCK, MISO, PA13 (U1 pin 22), ~D4, ~D5, ~D11, ~D13, ~D10, ~D12, D6, D7, SDA, SCL, USB- (on D1), USB+ (on D2), GND, 3V3, PB22 (U1 pin 37), PB23 (U1 pin 38), PA27 (U1 pin 39), RST, PA28 (U1 pin 41), GND, VDDCORE (on C21), 3V3, CLK (on J2), DIO (on J2), A5 and PB03 (U1 pin 48). Correct shorts when found.\n\nApply current limited (50mA) to GND and 5V pin. Current should still be about 6mA.\n\n# Bootloader\n\nBefore this board behaves like an `Arduino M0` (that you can program with the USB-port) you must first use the `Burn Bootloader`-function from the Arduino IDE. Choose the board `Arduino M0`, then choose your desired `Programmer` then choose `Burn Bootloader`.\n\n![](arduino-burn-bootloader.png)\n\n# Invisible Blink\n\nConnect USB. A new serial port should appear in the device manager.\n\nOpen the example Blink sketch and flash it to the MCU. Measure voltage on GND and ~D13, it should alternate between 0V and 3.3V.\n\n# Done\n\nDone!\n\n[![License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://opensource.org/licenses/Apache-2.0)","project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fatoomnetmarc%2Fsamd21-breakout","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Fatoomnetmarc%2Fsamd21-breakout","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fatoomnetmarc%2Fsamd21-breakout/lists"}