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alexforencich / xboot

XBoot Extensible Bootloader
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Start bootloader section address #38

Closed Romarm closed 6 years ago

Romarm commented 6 years ago

I have some misunderstanding with start bootloader section address. I use atmega644p device. According to "Atmel-8011-8-bit-AVR-Microcontroller-ATmega164P-324P-644P_datasheet" table 23-13 Boot Reset Address is 0x7000 while BOOTSZ1=0 and BOOTSZ0=0. But in xboot Makefile BOOT_SECTION_start defined as 0xE000. ... ifneq ($(filter $(MCU_S), m64 m640 m644 m644p m644pa m645 m6450 m649 m649p m6490),) ifeq ($(BOOTSZ), 0) BOOT_SECTION_START =0x00E000 BOOT_SECTION_SIZE =0x002000 endif ... In fact, when I read chip flash after xboot flashing I see code at 0xE000 as defined in xboot Makefile. What is wrong?

alexforencich commented 6 years ago

These constants are defined in bytes; the figures in the datasheet are in 16 bit words. 0x7000 in words is 0xE000 in bytes.

Romarm commented 6 years ago

Oh, Thank You!