4 I/O Pin Assignment
The module pin assignment is shown in the following table. The column "MCU Pin" is referring to the ATSAMR21G18 datasheet [SAMR21]. The column “Port Configuration” is intended to determine the required SAMR21 port configuration.
| Module Pin | Function | MCU Pin | Port Configuration |
|---|---|---|---|
| 1 | GND | — | — |
| 2 | GND | — | — |
| 3 | VCC | — | — |
| 4 | VCC | — | — |
| 5 | RSTN | 40 | — |
| 6 | SPI_CS | 26 | SERCOM1; MUX=C; DOPO=0x1; Host PAD1 |
| 7 | SPI_MOSI | 27 |
SERCOM1; MUX=C; DOPO=0x1 Host PAD2 For client operation this pin is MISO |
| 8 | SPI_MISO | 25 |
SERCOM1; MUX=C; DIPO=0x0 Host PAD0 For client operation this pin is MOSI |
| 9 | SPI_SCLK | 28 | SERCOM1; MUX=C; DOPO=0x1 Host PAD3 |
| 10 | GPIO | 41 | PA28 (Yellow LED; low active) |
| 11 | — | — | Not connected |
| 12 | GND | — | — |
| 13 | RXD1 | 12 |
SERCOM0; MUX=D; PAD[3] RXPO=0x3 Can be used for UART with RTS/CTS |
| 14 | TXD1 | 15 |
SERCOM0; MUX=C; PAD[0] TXPO=0x0 Can be used for UART with RTS/CTS |
| 15 | — | — | Not connected |
| 16 | — | — | Not connected |
| 17 | FEM_RX_TX | 22 | PA13; MUX=F; FECTRL3 (LED red) |
| 18 | ANT_DIV_P | 21 | PA12; MUX=F; FECTRL2 (LED green) |
| 19 | GPIO/USB_DM | 33 | PA24 for USB MUX=G |
| 20 | GPIO/USB_DP | 34 | PA25 for USB MUX=G |
| 21 | — | — | Not connected |
| 22 | RXD0 | 24 | SERCOM2; MUX=C; PAD[3]; RXPO=0x3 |
| 23 | TXD0 | 23 | SERCOM2; MUX=C; PAD[2]; TXPO=0x1 |
| 24 | AREF | 9 | MUX=B; disable digital |
| 25 | ADC0 | 10 |
MUX=B; AIN[1]; disable digital Can be used for UART with RTS/CTS |
| 26 | ADC1 | 11 |
MUX=B; AIN[2]¸ disable digital Can be used for UART with RTS/CTS |
| 27 | — | — | Not connected |
| 28 | — | — | Not connected |
| 29 | GND | — | — |
| 30 | SWCLK | 45 | Programming interface |
| 31 | SWDIO | 46 | Programming interface |
| 32 | — | — | Not connected |
| 33 | ATECC508 GPIO | — | Crypto IC GPIO with intrusion detection feature |
| 34 | — | — | Not connected |
| 35 | — | — | Not connected |
| 36 | I2C SCL | 32 | PA23 SERCOM3 PAD1 MUX=C |
| 37 | I2C SDA | 31 | PA22 SERCOM3 PAD0 MUX=C |
| 38 | — | — | Not connected |
| 39 | — | — | Not connected |
| 40 | — | — | Not connected |
| 41 | GND | — | — |
| 42 | GND | — | — |
| 43 | GND | — | GND reference for pin44 |
| 44 | P2 | — | Do not use the connector if this pad is in use. |
| 45 | GND | — | GND reference for pin44 |
| 46 | GND | — | GND reference for pin47 |
| 47 | P1 | — | Do not use the connector if this pad is in use. |
| 48 | GND | — | GND reference for pin47 |