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ON-BOARD PROGRAMMING METHODS FOR XFLASH AND HDFLASH ST7 MCUs

2.2.4 USB-based example

In this example, the USB link is used for the

Protocol Layer interfaces and Data Transfer sup-

port.

This implementation is an ideal example of IAP because the fact that the USB link is already

available means that you get a connection to the programming tool for free. On top of that, the

USB protocol itself allows the same media support to be used for the New Data and the Com-

mand/Status transfer.

The final scheme is there slightly different from Figure 2 since the

Data Transfer layer and the

Protocol layer interfaces are merged into a DFU driver.

Figure 4. Device Firmware Upgrade by USB

ST7 MCU

New Data

Commands

USB

Host PC Computer

Status

Protocol layer

IAP driver

DFU driver

MCU RAM

Commands

Status