I really need some support.Please suggest. BLreset : >boottimeout Question is that Boot.c set Bootdelay to 2 seconds.Then why they are using like above. Though, in the App linker script, they explictely declared like below in the MEMORY section: BLreset : ORIGIN = 0x100, LENGTH = 0x4. Linker script ( btlmx.ld) for Bootloader was generated automatically, and uploaded but. Then, selected Bootloader Type: USBDEVICE and checked Build a Bootloader.
In the Bootloader program, they defined constant "USER_PROG_RESET"(0x100) which tells where the Reset vector is mapped. For the bootloader application, I went to MPLAB Harmony configuration v2.06, and choose Harmony Framework Configuration->Bootloader Library and the checked Use Bootloader Library.
Q2: After successful bootloader operation or boot timeout, it must call user application. This means the project must use a different linker definition file but it can be derived from the original one easily. But I don't see that this is mapped in both program and script. Thus the default linker file provided with RAIL examples is not suitable for applications using bootloader. For this, the device's hardware Reset vector(addresses 000000h and 000002h) should have starting address of Bootloader (0x400).
One linker script for bootloader and application code#
Though, I have some confusion in understanding about Reset Vector: Well, let's assume my Boot loader start at: data (a!xr) : ORIGIN = 0x0800, LENGTH = 0x18000 reset : ORIGIN = 0x0000, LENGTH = 0x4 ivt : ORIGIN = 0x0004, LENGTH = 0xFC aivt : ORIGIN = 0x0104, LENGTH = 0xFC program (xr) :ORIGIN = 0x400, LENGTH = 0x1000 /*Boot loader starts */ Application starts at: data (a!xr) : ORIGIN = 0x0800, LENGTH = 0x18000 reset : ORIGIN = 0x0000, LENGTH = 0x4 ivt : ORIGIN = 0x0004, LENGTH = 0xFC aivt : ORIGIN = 0x0104, LENGTH = 0xFC app_ivt : ORIGIN = 0x1402, LENGTH = 0x01FC program (xr) : ORIGIN = 0x1602, LENGTH = 0x141F6 /* User code starts */ Q1:After every device reset,bootloader has to be called first. So,the Real IVT points to APP_IVT which has the address of the ISR. Linker script: When a hex file is compiled from a source, it contains information about where in program memory it should be written.By default it starts at address 0x00 and continues as far as it needs to go, but this would overwrite the bootloader.So you need something to tell MPLAB where in memory it can put code this is done by a linker. What I understood is BL script owns the Real IVT and APP script will generate new IVT table in its space.
Hello All, I am going to develop Bootloader for PIC24FJ128GB206.I read AN1157 and some posts in the same forum to get understanding on bootloader.
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