Freescale Semiconductor DSP56366 User Manual

Page 261

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DSP56366 Bootstrap Program

DSP56366 24-Bit Digital Signal Processor User Manual, Rev. 4

Freescale Semiconductor

A-9

; HROD = 0 Host request is active when enabled

; spare = 0 This bit should be set to 0 for

; future compatability

; HEN = 0 When the HPCR register is modified

; HEN should be cleared

; HAEN = 0 Host acknowledge is disabled

; HREN = 1 Host requests are enabled

; HCSEN = 1 Host chip select input enabled

; HA9EN = 1 Enable address 9 input

; HA8EN = 1 Enable address 8 input

; HGEN = 0 Host GPIO pins are disabled

HDI08CONT

bset #HEN,x:M_HPCR ; Enable the HDI08 to operate as host

; interface (set HEN=1)

jclr #HRDF,x:M_HSR,* ; wait for the program length to be

; written

movep x:M_HORX,a0

jclr #HRDF,x:M_HSR,* ; wait for the program starting address

; to be written

movep x:M_HORX,r0

move r0,r1

do a0,HDI08LOOP ; set a loop with the downloaded length

HDI08LL

jset #HRDF,x:M_HSR,HDI08NW ; If new word was loaded then jump to

; read that word

jclr #HF0,x:M_HSR,HDI08LL ; If HF0=0 then continue with the

; downloading

enddo ; Must terminate the do loop

bra <HDI08LOOP

HDI08NW

movep x:M_HORX,p:(r0)+ ; Move the new word into its destination

; location in the program RAM

nop ; pipeline delay

HDI08LOOP

;========================================================================

; This is the exit handler that returns execution to normal

; expanded mode and jumps to the RESET vector.

FINISH

andi #$0,ccr ; Clear CCR as if RESET to 0.

jmp (r1) ; Then go to starting Prog addr.

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