flash
发布时间：2020-12-15 06:18:42 所属栏目：百科 来源：网络整理
导读：;************************************************************************** ; ? FLASH.ASM - routine to make user code bootable from a flash eeprom ; ; ? The FLASH program should be assembled separately. ?Load your routine,? ; ? then load F
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;**************************************************************************
; ? FLASH.ASM - routine to make user code bootable from a flash eeprom
;
; ? The FLASH program should be assembled separately. ?Load your routine,?
; ? then load FLASH,set the register R1 to indicate the end of your code?
; ? (the last address) and run FLASH from program address $7FE0.
;
;
; ? 3 Nov. 1994 : version 1.0 ? rlr/ljd
; ?13 Apr. 1995 : ? ? ? ? 1.1 ? rlr - force write to low byte (enable_prot)
; ?25 Oct. 1995 : ? ? ? ? 1.2 ? rlr - correct conversion to sector count
; ?29 Mar. 1996 : ? ? ? ? 1.3 ? mnw - added user discription
; ?06 Feb. 1997 : ? ? ? ? 1.4 ? wtb - added comments from Johan Forrer
; ?04 Apr. 1997 :
?1.5 ? updated with variable end_address by F.Kuenle & M.Maier?
;
:
so you no longer have to manually set R1. ?the code just
;
sets it to the highest legal address?
;
for you - d.r.
;
; ? copyright (C) Motorola 1994
;
; ? execute with: ?R1 containing last address to store
; Comments from Johan Forrer KC7WW
; 1) Assemble your aplication program with the "-l" option. Check the
; ? ?LAST address in P. Remember ONLY P code will be saved into EEPROM,?
; ? ?this means that coefficients or other constants need to be transferred?
; ? ?from P->X/Y as part of the user's code.
; 2) Load this user program into EVM's memory using the debugger.
; 3) Load FLASH.CLD into the EVM's memory.
; 4) Modify register R1 to contain the LAST address as in (1). Remember that
; ? ?the EVM only accepts the value AFTER the register contents is
; ? ?displayed in HIGHLIGHED text.
; 5) "GO 7F00" or simply "GO" and wait till the debugger returns to diplaying
; ? ?"DEBUG" - it may take a few seconds.
; 6) Power down or RESET and the application will now restart from?
; ? ?FLASH EEPROM.
; 7) Reminder that the maximum address range for the FLASH EEPROM on the
; ? ?EVM is from 8000 - FFFFh. However,the ROM bootstrap on the 56002 will
; ? ?load 512 words starting at C000h at boot time. This then means that
; ? ?you may only utilize the FLASH EEPROM space corresponding from
; ? ?8000-BFFFh,a mere 4000h bytes,or 1555h 24-bit words. This will
; ? ?be equal to saving the address range P:0000 - 1554h. The program
; ? ?"FLASH.ASM" will write code in 64 word blocks,that means that the
; ? ?highest P-address may only be >>>1540h<<<. This is the highest value?
; ? ?that may be entered safely into R1 before programming the EEPROM.
;**************************************************************************
BCR ? ? ? ? ? ? equ ? ? $FFFE ? ? ? ? ? ;Bus Control Register
PLL_CTRL ? ? ? ?equ ? ? $FFFD ? ? ? ? ? ;PLL Control Register
begin_address ? equ ? ? $7FE0 ? ? ? ? ? ;The loader will be copied to p:$7fe0
end_address ? ? equ ? ? $153f ? ? ? ? ? ;feste Userprg.endadresse
org ? ? p:$7F00
main
;---------------------------------------------------------------------------
; ?An external boot-ROM must have the lowest byte of data at the lowest
; ?address. ?(i.e.,?ROM Address $C000 --- P:0000 low ? ?byte
; ? ? ? ? ? ? ? ? ? ?ROM Address $C001 --- P:0000 middle byte
; ? ? ? ? ? ? ? ? ? ?ROM Address $C002 --- P:0000 high ? byte
; ? ? ? ? ? ? ? ? ? ?ROM Address $C003 --- P:0001 low ? ?byte ....)
;---------------------------------------------------------------------------
movep ? #$261009,x:PLL_CTRL ? ? ;set PLL for MF=10,40 MHz VCO out
movep ? #$B0B0,x:BCR ? ? ? ? ? ?;at 40MHz,T=25ns,11 wait states in P:
;------ move the bootstrap loader into FLASH at P:$C000
move ? ?#end_address,r1 ? ? ? ? ;set end-address of userprg !!!
move ? ?r1,P:boot+$E ? ? ? ? ? ?;modify boot for length
move ? ?#boot,r0 ? ? ? ? ? ? ? ?;first DSP address to save
move ? ?#$C000,r2 ? ? ? ? ? ? ? ;flash starting address
jsr ? ? WR_FLASH ? ? ? ? ? ? ? ?;save 64 words
move ? ?r1,A ? ? ? ? ? ? ? ? ? ?;convert word cnt to sector cnt.
rep ? ? #6
asr ? ? A?
move ? ?A1,r1
nop
move ? ?(r1)+
move ? ?#$8000,r2 ? ? ? ? ? ? ? ;address of initial FLASH address
move ? ?#$0000,r0 ? ? ? ? ? ? ? ;r0 points to input code
do ? ? ?r1,loop ? ? ? ? ? ? ? ? ;write sectors
jsr ? ? WR_FLASH
loop
movep ?#$0000,x:BCR
debug
jmp ? ?*
;************************************************************************
; ? WR_FLASH
; ? This routine writes 64 (24-bit) words from DSP RAM to FLASH EEPROM
;?
; ? ? ? enter with: ? ? r2 pointing to starting EEPROM Byte Address
; ? ? ? ? ? ? ? ? ? ? ? r0 pointing to first DSP word to save
;
;-------------------------------------------------------------------------
; ? first,move 64 bytes - this includes 21 words + low byte of 22nd
;-------------------------------------------------------------------------
WR_FLASH
jsr ? ? disable_protect
do ? ? ?#21,move_codeA ? ? ? ? ?;move 63 bytes
move ? ?P:(r0)+,A ? ? ? ? ? ? ? ;get 3 byte word
move ? ? ? ? ? ?A1,x:(r2)+ ? ? ?;move low ?byte to FLASH EEPROM
rep ? ? #8
lsr ? ? A ? ? ??
move ? ? ? ? ? ?A1,x:(r2)+ ? ? ?;move mid ?byte to FLASH EEPROM
rep ? ? #8
lsr ? ? A ? ? ??
move ? ? ? ? ? ?A1,x:(r2)+ ? ? ?;move high byte
move_codeA
;*** 64th byte
move ? ?P:(r0)+,A ? ? ? ? ? ? ? ;get next 3 byte word
move ? ? ? ? ? ?A1,x:(r2)+ ? ? ?;move low ?byte
jsr ? ? delay_200u ? ? ? ? ? ? ?;wait 200 microseconds to enter?
;...program cycle
jsr ? ? program_complete ? ? ? ?;wait for programming cycle to?
;...finish
;-------------------------------------------------------------------------
; ? then,move another 64 bytes - mid and high bytes of 22nd word followed
; ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? by 20 words and then the low and mid
; ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? bytes of the next word
;-------------------------------------------------------------------------
jsr ? ? disable_protect
rep ? ? #8 ? ? ? ? ? ? ? ? ? ? ?
lsr ? ? A ? ? ??
move ? ? ? ? ? ?A1,x:(r2)+ ? ? ?;move high byte
do ? ? ?#20,move_codeB ? ? ? ? ?;move 60 bytes
move ? ?P:(r0)+,x:(r2)+ ? ? ?;move high byte
move_codeB
;*** 63rd byte ***
move ? ?P:(r0)+,x:(r2)+ ? ? ?;move low byte
rep ? ? #8
lsr ? ? A ? ? ? ? ? ? ? ? ? ? ? ;*** 64th byte ***
move ? ? ? ? ? ?A1,x:(r2)+ ? ? ?;move mid ?byte to FLASH EEPROM
jsr ? ? delay_200u ? ? ? ? ? ? ?;wait 200 microseconds to enter?
;...program cycle
jsr ? ? program_complete ? ? ? ?;wait for programming cycle to?
;-------------------------------------------------------------------------
; ? lastly,move another 64 bytes - high bytes of last word followed
; ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? by 21 words
;-------------------------------------------------------------------------
jsr ? ? disable_protect
rep ? ? #8
lsr ? ? A ? ? ??
move ? ? ? ? ? ?A1,x:(r2)+ ? ? ?;move high byte of last word
do ? ? ?#21,move_codeC ? ? ? ? ?;move 63 bytes
move ? ?P:(r0)+,x:(r2)+ ? ? ?;move high byte
move_codeC
jsr ? ? delay_200u ? ? ? ? ? ? ?;wait 200 microseconds to enter?
;...program cycle
jsr ? ? program_complete ? ? ? ?;wait for programming cycle to?
;...finish
jsr ? ? enable_protect
rts
;***************************************************************************
;----------------------------------------------------------------------------
; ?enable_protect - Software data Protection routine
;
;----------------------------------------------------------------------------
enable_protect ?
move ? ?#>$AA,x0
move ? ? ? ? ? ?x0,x:$D555 ? ;Atmel needs $5555
move ? ?#>$55,x:$AAAA ? ;Atmel needs $2AAA
move ? ?#>$A0,x:$D555 ? ;writes are now enabled
rts
??
;---------------------------------------------------------------------------
; ?disable_protect - Disables Software Data protection
;?
; ?This code writes the appropriate data to the FLASH part that disables
; ?the write protection from the FLASH and allows the part to be loaded.
;
;---------------------------------------------------------------------------
disable_protect
move ? ?#>$AA,x:$D555
move ? ?#>$55,x:$AAAA
move ? ?#>$80,x:$D555
move ? ?#>$AA,x:$AAAA
move ? ?#>$20,x:$D555 ? ? ?;exit data protect state
rts
;---------------------------------------------------------------------------
; delay routine to be used to satisfy tBLC time requirement which is
; a minimum of 150 microseconds.
; Write Pulse Width,Write Pulse Width High requires a minimum of
; 3000 Icycles for 40MHz clock. ?(50ns/Icycle)
;---------------------------------------------------------------------------
delay_200u ?
rep ? ?#4000 ? ? ?; delay of 200 micro seconds.
nop
rts
? ?
;---------------------------------------------------------------------------
; ?program_complete - routine to poll for the end of the programming cycle
;
; ?The AT29C256 will toggle bit 6 on successive reads until the program
; ?cycle completes. ?When bit 6 stabilizes,the device is no longer in
; ?a programming cycle.
;---------------------------------------------------------------------------
program_complete
btst ? ?#6,x:$8000 ? ? ? ? ? ? ?;check the initial status of bit 6
jcs ? ? check_set
check_clr ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ;---go here if bit 6 is clear---
jsr ? ? delay_200u ? ? ? ? ? ? ?;no need to hurry,give it a rest
btst ? ?#6,x:$8000 ? ? ? ? ? ? ?;test bit 6...it was clear
jcs ? ? check_set ? ? ? ? ? ? ? ;if it is now set,continue...
rts
check_set ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ;---go here if bit 6 is set---
jsr ? ? delay_200u ? ? ? ? ? ? ?
btst ? ?#6,x:$8000 ? ? ? ? ? ? ?;test bit 6...it was set
jcc ? ? check_clr ? ? ? ? ? ? ? ;if it is now clear,continue...
rts
;**************************************************************************
; ?this is the bootstrap loader
; ?it is loaded into the memory at boot time and then moves the?
; ?application code into DSP RAM
;
boot
org ? ? p:0,p:*
;----------------------------------------------------------------------------
;The following code moves the loader code from the P:RAM.
;----------------------------------------------------------------------------
begin ??
move ? ?#reloc,r0 ? ? ? ? ? ? ? ; R0 points to loader code.
move ? ?#begin_address,r1 ? ? ? ; R1 points to runtime loader loc.
do ? ? ?#load_length,_move_code ; Move loader code to runtime loc.
move ? ?p:(r0)+,x0 ? ? ? ? ? ? ?; Read loader code from load ? ?loc.
move ? ?x0,p:(r1)+ ? ? ? ? ? ? ?; Write loader code to ?runtime loc.
_move_code
;----------------------------------------------------------------------------
;The following code moves the user's code from the flash to P:RAM.
;----------------------------------------------------------------------------
jmp ? ? load
reloc
org ? ? p:begin_address,p:
load ? ?move ? ?#$0000,r0 ? ? ? ? ? ? ? ; copy EEPROM into P:RAM @ $0000
move ? ?#$8000,r1 ? ? ? ? ? ? ? ; R1 points to the code in flash
move ? ?#1000,r2 ? ? ? ? ? ? ? ?; R2 contains the length of code?
; in words.
do ? ? ?r2,_ld_loop1 ? ? ? ? ? ?; Loop once for each word of code.
do ? ? ?#3,_ld_loop2 ? ? ? ? ? ?; Loop 3 times for each word.
movem ? p:(r1)+,a2 ? ? ? ? ? ? ?; Load byte from flash.
rep ? ? #8 ? ? ? ? ? ? ? ? ? ? ?; Shift eight times to move
asr ? ? a ? ? ? ? ? ? ? ? ? ? ? ; byte into correct position.
_ld_loop2
movem ? a1,p:(r0)+ ? ? ? ? ? ? ?; Stores 24-bit word.
_ld_loop1
jmp ? ? 0 ? ? ? ? ? ? ? ? ? ? ? ; Jump to the reset vector.
load_length ? ? equ ? ? *-load
end
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