a752c7ab
 elopes
add first test an...
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/* ARM code to run user code */
/* on the LPC23xx chips, the bootloader defaults to using the RC */
/* osciallator and it activates the PLL to create 14.78 MHz, even */
/* if there is no crystal. However, when we use try to jump to */
/* the user's code, their startup routine may (incorrectly) assume */
/* the PLL is not enabled and crash if it is. So in addition to */
/* remapping the reset vector to flash, we have to shut off the */
/* PLL so the user's startup code sees the same conditions as it */
/* would following a hard reset */
begin:
adr r0, const
ldr r1, [r0] /* r1 points to MEMMAP register */
ldr r2, [r0,#4] /* r2 points to PLLCON */
ldr r3, [r0,#8] /* r3 points to PLLFEED */
mov r0, #1
str r0, [r1] /* remap interrupt vectors to flash */
mov r4, #0xAA
mov r5, #0x55
str r0, [r2] /* disconnect the PLL, PLLCON = 1 */
str r4, [r3]
str r5, [r3]
mov r0, #0
str r0, [r2] /* disable the PLL, PLLCON = 0 */
str r4, [r3]
str r5, [r3]
mov pc, #0 /* and then jump to the user's code */
const:
.int 0xE01FC040 /* MEMMAP register */
.int 0xE01FC080 /* PLLCON */
.int 0xE01FC08C /* PLLFEED */
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