DLPU114A August 2024 – November 2024 DLPC8445
The controller employs a Boot ROM and associated boot software. This resident boot code consists of the minimum code necessary to complete the program loading from Flash to internal RAM at power-up. Therefore, an external flash device is required to store the device firmware.
The Boot ROM also contains software that will receive I2C/USB interface commands at power-up where the commands are specifically for programming or re-programming the controller’s flash device. Before programming or reprogramming, the flash device can have valid firmware, or corrupted firmware, or the flash device can be blank.
Boot ROM commands will be applicable only when the system is in Boot hold mode. The system can get in Boot hold mode when either the Boot hold pin (STAY_IN_BOOT) is set, or flash is empty or has corrupted Secondary Boot firmware, or when main application (MainApp) explicitly goes to Boot ROM for firmware upgrade. In other scenarios boot software will load the valid MainApp and will transfer control to MainApp or into Secondary Boot. Command support will be limited in Boot ROM.