Motorola DSP56301 User Manual

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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:

;