55 lines
1.4 KiB
NASM
55 lines
1.4 KiB
NASM
; Non-volatile memory routines
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FLASH_base .field 0x400FD000 ; Flash control base address
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SYSCONF .field 0x400FE000 ; System memory control base address
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WRKEY0 .field 0x71D5 ; Write key when BOOTCFG address KEY bit is 0
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WRKEY1 .field 0xA442 ; Write key when BOOTCFG address KEY bit is 1
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FLASH_END .field 0x3FFFF ; End of flash memory region
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; Flash control offsets
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FMA .equ 0x0 ; Target address (0x0 - 0x3FFFF)
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FMD .equ 0x4 ; Data
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FMC .equ 0x8 ; Direct (single) write control - Writes 1 word
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FMC2 .equ 0x20 ; Buffered (wide) write control - Writes up to 32 words
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FWB_base .equ 0x100 ; Buffered data base offset (max: 0x17C)
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BOOTCFG .equ 0x1D0 ; Boot configuration address offset
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.text
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.thumb
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.global flashtest
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.align 2
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;; Writes a value near then end of the flash region
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;; Doesn't seem to survive resets, though
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;; TODO: Investigate reset-triggered FLASH clearing
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flashtest:
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;; Read word
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ldr r1,FLASH_END
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sub r1,r1,#8
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ldr r4,[r1] ; Read last word
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;; Write word
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; Write target address
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ldr r0,FLASH_base
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str r1,[r0,#FMA]
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; Write data to add to FLASH
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mvn r1,r4
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str r1,[r0,#FMD]
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; Trigger write
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ldr r1,WRKEY0 ; TODO: Select appropriate WRKEY based on BOOTCFG
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lsl r1,#0x10
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orr r1,#1
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str r1,[r0,#FMC]
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flashtest_await_write:
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ldrb r1,[r0,#FMC]
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tst r1,#1
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beq flashtest_complete
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flashtest_aight:
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b flashtest_await_write
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flashtest_complete:
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bx lr
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