Motorola DSP56301 user manual Write to Destination

Models: DSP56301

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bset

#M_BAAP,x:M_AAR1

; change AA1 polarity, in order to set

 

 

; it high

; (5) ACTIVATE SERIAL INTERFACE and SYNCHRONIZE

movep

#3,x:M_STXL

; load TX byte (READ opcode, B0)

bset

#M_SCTE,x:M_SCR

; activate SCI’s TX

; (6) TRANSMIT OPCODE and ADDRESS

 

jclr

#M_TDRE,x:M_SSR,*

; wait until byte is TXed (opcode, B0)

movep

#0,x:M_STXL

; load TX byte (address, B1)

jclr

#M_RDRF,x:M_SSR,*

; wait until byte is RXed (garbage, B2-)

movep

x:M_SRXL,a2

; read garbage

jclr

#M_TDRE,x:M_SSR,*

; wait until byte is TXed (address, B1)

movep

a2,x:M_STXL

; keep transmitting to maitain clock (ECHO)

jclr

#M_RDRF,x:M_SSR,*

; wait until byte is RXed (garbage, B1-)

movep

x:M_SRXL,a2

; read garbage

;first read two words: program_length and target_address

do #6,_rd_2_ws

jclr

#M_TDRE,x:M_SSR,*

; wait until byte is TXed (ECHO)

movep

a2,x:M_STXL

; keep transmitting to maitain clock (ECHO)

jclr

#M_RDRF,x:M_SSR,*

; wait until byte is RXed (valid, B0.)

movep

x:M_SRXL,a2

; read ONE

byte

(valid, B0...)

asr

#8,a,a

; pack it

 

 

_rd_2_ws

 

 

 

 

move

a1,r0

; starting address for load

move

a1,r1

; save starting address

; Now read program words

 

 

 

do

a0,_rd_n_ws

; read N words

 

do

#3,_rd_bytes

; read 3 bytes

 

jclr

#M_TDRE,x:M_SSR,*

; wait until byte is TXed (ECHO)

movep

a2,x:M_STXL

; keep transmitting to maintain clock (ECHO)

; (7) READ ONE BYTE

 

 

 

jclr

#M_RDRF,x:M_SSR,*

; wait until byte is RXed (valid, B6...)

movep

x:M_SRXL,a2

; read ONE

byte

(valid, B6...)

; (8) PACK IT

 

 

 

 

asr

#8,a,a

; pack it

 

 

_rd_bytes

 

 

 

 

; (10) WRITE TO DESTINATION

 

 

 

move

a1,p:(r0)+

; Store 24-bit result in P mem

nop

 

; pipeline delay

 

nop

 

; pipeline delay

 

_rd_n_ws

 

 

; (13) DEASSERT CHIP SELECT

 

bclr

#M_BAAP,x:M_AAR1

; change AA1 polarity, in order to set

 

 

; it high

bra <FINISH

; Boot from EPROM done

DSP56301 User’s Manual

A-15

Page 311
Image 311
Motorola DSP56301 user manual Write to Destination