Boot ROMMCF5253 Reference Manual, Rev. 1Freescale Semiconductor 19-7It will attempt to read the file IDEBOOT1.IDE and then verify the checksum. If this fails it triesIDEBOOT2.IDE eventually followed by IDEBOOT3.IDE.Typically, the data in the boot file is a second stage boot loader which performs the system initialization(SDRAM etc) and loads the application code.This second stage boot loader now performs the system boot, allowing the boot process to be customized,supporting different file systems, if necessary.Figure 19-2. Boot Loader IDE Interface19.3 Creating Appropriate Boot Record FilesFor serial boot modes typically at least two boot record headers must be added to the raw binary filegenerated by the user code. The first must be at the start of the file and should be a ‘Store Immediate’header with an appropriate load address and byte count, the second, an ‘Execute’ header, should be at theend of the file with an appropriate execute address.Multiple ‘Store Immediate’ headers can be used if several separate blocks of data need to be loaded beforecode execution can begin.Example utilities are available from Freescale to generate appropriate boot record files if required, contactyour local Freescale representative for further details.74LCX16245DIROE74LCX16245DIROEIDE InterfaceA1-A5D31-D15RWBUFENB2IDE_DIOWIDE_DIORIDE_IORDYGPIO04GPIO18IOWIORIORDYIRQRESETD15-D0A0-A2CS0, CS1MCF5253 Interface
