3.4.3.2 mikroBUS 2 Connector
The second mikroBUS 8-pin female header (J12) implements all mikroBUS features as described in the schematic below.
The reset feature is ensured (by default) by the processor reset line and can be controlled by the general reset line by swapping R198 and R199.
The second mikroBUS interface features an SPI bus shared with the first mikroBUS interface. Each interface has its own Chip Select line to its SPI interface (PB7 for the mikroBUS 2 interface). I/Os in common are PB3, PB4 and PB5. That means that the SPI interface cannot be used at the same time on the two mikroBUS interfaces.
The second mikroBUS interface features a two-wire interface (PC18 and PC19) shared with the first mikroBUS interface and with a 40-pin RPi connector. The end user must take care of the I²C addresses used on this nodes.
The PWM feature of the first mikroBUS interface (PD20) is shared with the blue LED control.
| Function | PIO | Mbus Signal | Pin No. | Pin No. | Mbus Signal | PIO | Function |
|---|---|---|---|---|---|---|---|
| Analog input | PD1 | AN | 1 | 16 | PWM | PD20 | PWM |
| Reset | nRST_MBUS | RST | 2 | 15 | INT | PC20 | Interrupt |
| SPI Chip Select | PB7 | SPI_NPCS | 3 | 14 | UART_RX | PC24 | UART receive (Mbus output to SAM) |
| SPI clock | PB5 | SPI_SPCK | 4 | 13 | UART_TX | PC23 | UART transmit (Mbus input from SAM) |
| SPI MOSI | PB4 | SPI_PISO | 5 | 12 | TWI_SCL | PC19 | TWI clock |
| SPI MISO | PB3 | SPI_MOSI | 6 | 11 | TWI_SDA | PC18 | TWI data |
| VCC | -- | 3.3V supply | 7 | 10 | 5V supply | – | VDD |
| GROUND | -- | GND | 8 | 9 | GND | – | Ground |