Motorola DSP96002 - Manual (Page 160)

9 - 4 DSP96002 USER’S MANUAL MOTOROLA
PAGE 132,50,0,10
; BOOTSTRAP CODE FOR DSP96002 -

Copyright 1988 Motorola Inc.
;
; Host algorithm / AND / external bus method.
;
; This is the Bootstrap program contained in the DSP96002. This program
; can load the internal program memory from one of 4 external sources.
; The program reads the OMR bits MA and MB to decide which external
; source to access.
; If MB:MA = 0X - load from 4,096 consecutive byte-wide P: memory
; locations (starting at P:$FFFF0000).
; If MB:MA = 10 - load internal PRAM thru Host Interface in Port A.
; If MB:MA = 11 - load internal PRAM thru Host Interface in Port B. BOOT
EQU $FFFF0000 ; The location in P: memory
; where the external byte-wide
; EPROM is expected to be mapped
M_HCRA EQU $FFFFFFEC ; Port A Host Control Register
M_HSRA EQU $FFFFFFED ; Port A Host Status Register
M_HRXA EQU $FFFFFFEF ; Port A Host Rec. Data Register
M_HCRB EQU $FFFFFFE4 ; Port B Host Control Register
M_HSRB EQU $FFFFFFE5 ; Port B Host Status Register
M_HRXB EQU $FFFFFFE7 ; Port B Host Rec. Data Register
ORG PL:$0 ; bootstrap code starts at P:$0
START MOVE #BOOT,R1 ; R1 = External P: address of
; bootstrap byte-wide ROM
MOVEI #0,R0 ; R0 = starting P: address of
; internal memory where program
; will begin loading.
; If this program is entered by changing the OMR to bootstrap mode,
; make certain that registers M0 and M1 have been set to $FFFFFFFF.
; Make sure the appropriate BCR register is set to $xxxxxxFx since
; EPROMs are slow.
; Make sure that the Port Selection Register is set to permit program
; memory accesses thru the required memory expansion port (Port A or B).
;
; The first routine will load 4,096 bytes from the external P memory
; space beginning at P:$FFFF0000 (bits 7-0). These will be condensed
; into 1,024 32-bit words and stored in contiguous internal PRAM memory
; locations starting at P:$0. Note that the first routine loads data
; starting with the least significant byte of P:$0 first.
; The Port Selection Register is not set by this program. It is set
; by HW Reset.
Figure 9-3. Assembler Source for DSP96002 Bootstrap Program (1 of 3)