SLVSGS5A December 2023 – June 2024 DRV3946-Q1
PRODUCTION DATA
The device supports an optional addressable SPI format to enable up to four devices to operate off the same chip select pin (nSCS). This also allows the usage of special broadcast commands that can enable all devices on the shared addressed bus to take certain actions simultaneously and to minimize pins required to interact with multiple devices.
When using the CMD2 broadcast command, the SDI data is delivered to all devices on the same addressable SPI bus. The SDO response is limited to a single device and the responding device is set with the node address bits (A6, A5) in the SDI frame.
If not using the addressable SPI function, the nFAULT/NAD pin pullup resistor can be set to the default address (00) by using the 5.6 kΩ pull-up resistor value. The SPI then functions as a normal SPI by always setting the address bits A6 = 0b, and A5 = 0b.
During power up initialization, the device self assigns a node address (device address) that is based on the pull-up impedance on the nFAULT/NAD pin to VDD (see Table 6-12 for values). This address is mapped to the two MSBs of the 8 bit header (A6, B5) used in the SPI frame. This enables the user to assign an unique address to each driver (up to four drivers) using the node address feature on the nFAULT/NAD pin. Once initialized, the controller can access any specific register in any of the addressed devices with a single 24-bit frame. After initialization, this pin is then used for nFAULT assertion (open drain, active low) during normal device operation.
| A6 | A5 | Resistor to VDD on nFAULT/NAD Pin |
|---|---|---|
| 0 | 0 | 5.6 kΩ |
| 0 | 1 | 12 kΩ |
| 1 | 0 | 27 kΩ |
| 1 | 1 | 56 kΩ |