ZHCSQH2 July 2024 DRV81008-Q1
ADVANCE INFORMATION
The SPI of DRV81008-Q1 provides daisy chain capability. In this configuration several devices are activated by the same nSCS signal MCSN. The SDI line of one device is connected with the SDO line of another device, in order to build a chain. The end of the chain is connected to the output and input of the master device, MO and MI respectively. The leader device provides the clock MCLK which is connected to the SCLK line of each device in the chain.
In the SPI block of each device, there is one shift register where each bit from SDI line is shifted in each SCLK. The bit shifted out occurs at the SDO pin. After sixteen SCLK cycles, the data transfer for one device is finished.
In single chip configuration, the nSCS line must turn logic high to make the device acknowledge the transferred data. In daisy chain configuration, the data shifted out at device 1 has been shifted in to device 2. When using three devices in daisy chain, several multiples of 8 bits have to be shifted through the devices (depending on how many devices with 8 bit SPI and how many with 16 bit SPI). After that, the MCSN line must turn logic high.