The SPI interface consists of several digital lines and the SPI supply. If routing of the interface lines is not done properly, communication errors can occur. It should be prevented that SPI lines can pickup noise and possible interfering sources should be kept away from the interface.

Pickup of noise can be prevented by ensuring that the SPI ground line is routed together with the digital lines as much as possible to the respective pins. The SPI interface should be connected by a separate own ground connection to the DGND of the DLPA3000 (Figure 11-3). This prevents ground noise between SPI ground references of DLPA3000 and DLPC due to the high current in the system.

Figure 11-3 SPI Connections

Interfering sources should be kept away from the interface lines as much as possible. If any power lines are routed too close to the SPI_CLK, it is possible it will lead to false clock pulses and, thus, communication errors.