Motorola DSP56301 - Manual (Page 300)

A -4 DSP56301 User’s Manual
; correspondingly drive the 24-bit data mapped into the 32-bit PCI bus word.
;
; Note that for the synchronization purposes, the DSP-to-PCI clock ratio
; should be more than 5/3.
;
;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; If MD:MC:MB:MA=x101, then it loads the program RAM from the Host
; Interface programmed to operate in the Universal Bus mode supporting
; ISA (slave) glue less connection.
;
; Using Self-Configuration mode, the base address in the CBMA is initially
; written with $2f, which corresponds to an ISA HTXR address of $2fe
; (Serial Port 2 Modem Status read only register).
;
; The HI32 bootstrap code expects to read 32 consecutive times the "magic
; number" $0037. Subsequently the bootstrap code expects to read a 16-bit word
; that is the designated ISA Port Address; this address is written into the
; CBMA. The HOST Processor must poll for the Host Interface to be reconfigured.
; This must be done by reading the HSTR and verifying that the value $0013 is
; read. From this moment the HOST Processor can start writing data to the
; Host Interface.
;
; The HI32 bootstrap code expects first to read a 24-bit word (see
; Note below) specifying the number of program words, then a
; 24-bit word specifying the address to start loading the program
; words, and then 24-bit word for each program word to be loaded.
;
; The program words will be stored in contiguous PRAM memory
; locations beginning at the specified starting address. After
; the program words are read, program execution starts from the same
; address where loading started.
;
; The Host Interface bootstrap load program can be stopped by setting the
; Host Flag 0 (HF0) in the HCTR register. This will start execution of the
; loaded program from the specified starting address.
;
; Note: This ISA connection implies 16-bit data width access only and
; that the number of transferred 16-bit wide words must be
; even.
;
; The 24-bit words must be packed into 16-bit ISA words and then sent
; by the HOST Processor in the following sequence:
;
; | M0 | L0 |
; | L1 | H0 |
; | H1 | M1 |
;
; The boot program will convert every three 16-bit wide host words to two
; 24-bit wide 56301 opcodes in the following format:
;
; | H0 | M0 | L0 |
; | H1 | M1 | L1 |
;
; The Host Processor must program the Host Interface to operate in the
; zero fill mode (HTF1-HTF0 = 01 in HCTR).
;
; Sugested 56301 to ISA connection:
;