Applications Information

The proper use of bypass capacitors reduces noise generated by the IC into the ground plane. The Pin Descriptions table indicates which pins should be connected to bypass capacitors, and the appropriate ground plane.

It is recommended that one instance of a bypass capacitor should be connected to each power pin/ball of the IC package. For example, if the Pin Descriptions table shows four device pins associated with voltage supply A, a separate capacitor should be connected to each pin for a total of four capacitors.

Capacitors should be placed as close as possible to their corresponding device pins. When more than one value of capacitor per pin is recommended, the capacitors should be placed in parallel starting with the lowest value capacitor closest to the pin.

The bootloader interface options are shown in Table 8. The bootloader is activated if the activation pins are in their active state before exiting any reset and remain in that state until the bootloader sends the first command prompt through the interface. If the pins are not in their active state, the device will perform a secure boot and, if successful, begin execution of the application code. The design must ensure the activation pins and the RSTN pin are available to the host so it can activate the bootloader.

Note: It is recommended that at least one of the bootloader activation pins are connected to a 10kΩ pull-up resistor to ensure that the pins are in their inactive state during reset.