David Van Horne's EEPROM.asm
Handler for the internal EEPROM, coded to save and recall pot values for DS1806 above, but you can use it for anything.
Handler for the internal EEPROM, coded to save and recall pot values for DS1806 above, but you can use it for anything.
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;*************************************************************************** ; ; File Name :'EEPROM.asm" ; Title : ; Date : ; Version : ; Support telephone :765 287 1987 David B. VanHorn ; Support fax :765 287 1989 ; Support Email :dvanhorn@cedar.net ; Support Snail ;1104 E 13th St, Muncie IN 47302 ; Target MCU :AT90S8515 ; ;***************************************************************************; ; D E S C R I P T I O N ; ;Example code for using the onboard EEPROM including safe read and write ; ;***************************************************************************; ; M O D I F I C A T I O N H I S T O R Y ; ; ; rev. date who why ; ---- -------- --- ------------------------------------------ ; 0.01 98.11.30 dvh Creation ; ;******************************************************************** ;Here, we take each setting from SRAM or Registers, and put them into ;EEPROM for safekeeping ;******************************************************************** ; Save_Settings: push TEMP ; push TEMP2 ; ldi XL,$01 ;Pointing to the lowest cell ldi XH,$00 ;+1 (Don't use 00) ;Save pot setting lds TEMP,POT1; rcall Save_EE ; lds TEMP,POT2; rcall Save_EE ; lds TEMP,POT3; rcall Save_EE ; lds TEMP,POT4; rcall Save_EE ; lds TEMP,POT5; rcall Save_EE ; lds TEMP,POT6; rcall Save_EE ; ldi XL,$FF ;Pointing to unused memory ldi XH,$FF ; rcall Read_EE ; pop TEMP2 ; pop TEMP ; ret ; ;******************************************************************** ;Loads settings into ram, but does NOT implement them to hardware ;******************************************************************** ; Load_Settings: push TEMP ; push TEMP2 ; ldi XL,$00 ;Start at 0001, not 0000 ldi XH,$00 ; rcall Read_EE ;Dummy read ;Recall pot settings rcall Read_EE ; sts POT1,TEMP; rcall Read_EE ; sts POT2,TEMP; rcall Read_EE ; sts POT3,TEMP; rcall Read_EE ; sts POT4,TEMP; rcall Read_EE ; sts POT5,TEMP; rcall Read_EE ; sts POT6,TEMP; ldi XL,$FF ;Pointing to unused memory ldi XH,$FF ; rcall Read_EE ; pop TEMP2 ; pop TEMP ; ret ; ;******************************************************************** ;Put a single byte in EEPROM, safely per manual ;******************************************************************** ; Save_EE: in TEMP2,EECR;Poll for EECR,2=0 before continuing! andi TEMP2,$02; brne Save_EE ; out EEARH,XH;Point at the current cell out EEARL,XL; out EEDR,TEMP;Save the data sbi EECR,2 ; sbi EECR,1 ; ld TEMP,X+ ;Move the pointer. ret ; ; ;******************************************************************** ;Gets a single byte from EEPROM, safely ;******************************************************************** ; Read_EE: in TEMP2,EECR;Poll for EECR,2=0 before continuing! andi TEMP2,$02; brne Read_EE ;Potential to loop forever. out EEARH,XH;Set up the address out EEARL,XL; sbi EECR,1 ;Set EE Read Enable in TEMP,EEDR;Get the data ld TEMP2,X+;TEMP2 is junk, but the pointer is inc'd ret ; ; ;******************************************************************** .eseg;Put this in EEPROM .db 0 ;Location 0 is unused .db $32 ;Pot 1 t0 middle .db $32 ;Pot 2 .db $32 ;and so on .db $32 ; .db $32 ; .db $32 ; .db 0 .cseg;Back to code |