| ??? 01/13/09 12:33 Read: times Msg Score: +1 +1 Informative |
#161485 - you NEVER replace the bootloader Responding to: ???'s previous message |
you NEVER replace the bootloader which resides in low memory
CSEG AT 000h ;reset
ljmp app_cksm
CSEG AT 003h ;int 0
ljmp ISC_EI0
CSEG AT 00bh ;int 1
ljmp ISC_T0
CSEG AT 013h ;int 2
ljmp ISC_EI1
CSEG AT 01bh ;int 3 ;;T1
ljmp ISC_T1
........
// here switches between boot and app.
ISC_EI0: jnb GBboot,appET0 //int 0
ljmp ISR_EI0
appET0: ljmp APPBASE + 000h
ISC_T0: jnb GBboot,appT0 //int 1
ljmp ISR_T0
appT0: ljmp APPBASE + 004h
ISC_EI1: jnb GBboot,appEI1 //int 2
ljmp ISR_EI1
appEI1: ljmp APPBASE + 008h
ISC_T1: jnb GBboot,appT1 //int 3
lcall momma_spin0
reti
.......
app_cksm: mov dptr, #4000h ; app area extends from 4000h to fbffh
startup: setb GBboot
mov dptr,#0fb1fh
mov a,#0
movc a,@a+dptr
jz startAP ; if last page of flash is erased we are in app mode
ljmp ?C_STARTUP
startAP: clr GBboot
ljmp APPBASE + 060h
Erik PS mommspin0 is the routine for "thing that can not happen" |
| Topic | Author | Date |
| Own IAP boot loader for P89V51RB2 | 01/01/70 00:00 | |
| do you need ... | 01/01/70 00:00 | |
| Yes, unfortunately. | 01/01/70 00:00 | |
| many have made bootloaders that die not reside in a "boot fl | 01/01/70 00:00 | |
| Me too | 01/01/70 00:00 | |
| FlashMagic | 01/01/70 00:00 | |
| yes | 01/01/70 00:00 | |
| not necessarily | 01/01/70 00:00 | |
| that is correct, sorry | 01/01/70 00:00 | |
| Industrial device without Windows | 01/01/70 00:00 | |
| and so what | 01/01/70 00:00 | |
| Proper Coding? | 01/01/70 00:00 | |
| you NEVER replace the bootloader | 01/01/70 00:00 | |
| Bit GBboot | 01/01/70 00:00 | |
| a standard bit variable | 01/01/70 00:00 | |
Thank you, I have my solution | 01/01/70 00:00 | |
| options | 01/01/70 00:00 | |
| Options | 01/01/70 00:00 |