topic Re: No Reset Vector Value in glo file? in S12 / MagniV Microcontrollers

No Reset Vector Value in glo file?

everkimage — Tue, 28 May 2019 03:19:05 GMT

MCU is MC9S12XEQ512,compile the offical bootloader project and get one glo and one s19 file in the directory 'bin'.

In the project's prm file,I get source codes like:

VECTOR 0 _BootStart

VECTOR 1 _BootStart

VECTOR 2 _BootStart

In s19 file,i get the expected code:

S109FFFAF000F000F0002D

But in glo file,i get the unexpected code:

S20A7FFFFAF000F000F000AD

Description of PPAGE register in the datasheet,i get following words:

The fixed 16KB page from 0x4000~0x7FFF is the page number 0xFD;

The fixed 16KB page from 0xC000~0xFFFF is the page number 0xFF;

The 16KB page from 0x8000~0xBFFF mapped range is 0x780000~0x7FFFFF;

Upgrade processing use the glo file,but there is no Reset Vector Value(0xFFFA~0xFFFE) in glo file,how does this work?

everkimage — Tue, 28 May 2019 09:46:44 GMT

0x7FFFFA is Global Address.If ROMHM is 0,0xC000~0xFFFF will be mapped to 0x7FC000~0x7FFFFF.

Is it right?

kef2 — Tue, 28 May 2019 12:11:18 GMT

ROMHM affects what is mapped to non banked 0x4000-0x7FFF, either flash page 0xFD or EEPROM.

Your glo file is correct. Global 0x7FFFFA corresponds to non banked 0xFFFA. The math for S12X flash is this:

global_address = page_offset + page_size * PPAGE + 0x400000

page_size = 0x4000

page_offset = 0xFFFA % page_size = 0xFFFA & (page_size-1) = 0x3FFA

PPAGE = 0xFF

For details, as well for what 0x400000 comes from look at Figure 3-12. PPAGE Address mapping. 0x400000 corresponds to bit22=1.