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Figure 74. MSD update mode LED
Navigate to the PC’s file explorer and ensure that the SLN-LOCAL2-IOT kit is mounted as a USB MSD. A mounted kit is displayed
in the file explorer, as shown in
.
Figure 75. SLN-LOCAL2-IOT kit mounted as USB MSD
Drag and drop the generated BIN file for banks A or B into the MSD drive. This starts the download process and writes the BIN
file to the flash. After the image is programmed into the flash, it starts to execute.
9.3 Over-the-Air (OTA) and Over-the-Wire (OTW) updates
The bootloader supports several mechanisms to update the board’s firmware. The OTA/OTW updates are part of them. The OTA
and OTW updates are driven using a simple JSON interface, making it easy to implement the host-side code. The mechanism for
both OTA and OTW is the same. The only difference between the two is that the OTA update is performed over the air via Wi-Fi
and the OTW update is performed over UART. The OTA update interface is performed by hosting a TCP server on the kit which
receives the update-related JSON packets. The OTW update currently supports UART, but it can be extended to support any
serial interfaces, including SPI, TCP sockets, or even I
2
C. The OTA/OTW update method is described in more depth in this section.
9.4 Transfers
An OTA/OTW update is made up of individual JSON transfers. Each transfer contains two parts: a 4-byte size field and a JSON
message. This makes the OTA/OTW data interface compatible across a wide range of interfaces.
Figure 76. Transfer format
There are two types of messages passed: requests and responses.
shows the request and response flow.
NXP Semiconductors
Bootloader
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