Motorola DSP96002 User Manual

Page 160

9 - 4

DSP96002 USER’S MANUAL

MOTOROLA

PAGE 132,50,0,10

;

BOOTSTRAP CODE FOR DSP96002



;

; 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)