Plan the pin mux of an ATSAMD21G18A or ATSAMD21J18A visually, with SERCOM pad rules checked for you.
Loading ATSAMD Configuration Tool...
Every ATSAMD21 pin can carry several peripheral functions through the port multiplexer, and the datasheet table that lists them is long. This tool draws the package and lets you assign functions by clicking. Pick the microcontroller first. Then use the helpers next to the pin diagram:
Click a highlighted pin to assign the function. The tool suggests a signal name such as I2C_SDA, ADC_AIN0 or PWM0_WO0, which you can edit. Each pin holds one function at a time, so assigning a new one replaces the old one and two functions can never end up on the same pin. The summary lists every assignment as cards or a table, and Export saves it as JSON, CSV (opens in Excel) or plain text.
The pad constraints the tool applies come from the SERCOM chapter of the datasheet:
The DOPO, DIPO, TXPO and RXPO register fields must then match the pads you chose, so keep the export next to your SERCOM init code.
Building a SAMD21 board? Ask for a pre-fab schematic check before you order, or browse the KiCad design blocks.
The ATSAMD21G18A-MU in QFN-48 (the chip on the Arduino Zero and many SAMD21 boards) and the ATSAMD21J18A in TQFP-64. Pin data comes from the Microchip SAM D21/DA1 family datasheet (DS40001882F).
The SERCOM hardware fixes which pads carry which signal. In standard 2-wire I2C, SDA must be on PAD[0] and SCL on PAD[1]. PAD[2] and PAD[3] are only used in 4-wire mode. The tool highlights only the pins that satisfy these rules for the SERCOM instance and mode you pick.
Not yet. It exports the pin map as JSON, CSV or plain text so you can copy it into your firmware, schematic notes or a review document. KiCad schematic import is planned.
No. The configuration lives in the page while it is open. Export it before closing the tab if you want to keep it.