Stockly.com Forums - Serial Loading Program

I have a 1702A EPROM programmer loaned to me hooked up to my Altair 8800. This programmer can only be used with an Altair 8800 or S-100 based computer. With the help of some other people I was able to recreate the VTL-2 EPROM set for the Altair 680. The data is 768 bytes and I did not want to toggle in all of it!

So I used a simple serial loader program that I wrote a while back.

It is located at 0x1000 in memory and halts when the specified number of bytes has been read.

Here it is for those who are interested: (I assembled it using A85)

Code:

01 0000          ;Serial loader to get 768 bytes into RAM to burn VTL-2 for the 680

02 0000          ;

03 0000          .EQU CONT,0  ;CONTROL/STATUS PORT OF 2SIO CARD

04 0001          .EQU DATA,1  ;DATA PORT OF 2SIO CARD

05 0000          .EQU LOWADDR,H'00

06 0003          .EQU HIGHADDR,H'03

07 0000          ;

08 1000          .org H'1000  ;1000 IS STARTING POINT IN MEMORY

09 1000          ;.org H'7BFD ;31000 is STARTING POINT IN MEMORY

10 1000          ;

11 1000          ;

12 1000 3E03     RESET: MVI A, H'03   ;MASTER RESET

13 1002 D300      OUT CONT

14 1004 3E15      MVI A, H'15   ;CLK/16, 8N1, RTS LOW TX/RX INTERRUPTS DISABLED

15 1006 D300      OUT CONT

16 1008 210000    LXI H, H'0000 ;STARTING ADDRESS IN MEMORY FOR IMAGE

17 100B DB00     LOADLP:  IN  CONT    ;WAIT FOR RX BUFFER TO BE FULL

18 100D E601      ANI H'01

19 100F CA0B10    JZ  LOADLP

20 1012 DB01      IN  DATA    ;GET DATA

21 1014 77        MOV M, A    ;STORE TO RAM

22 1015 23        INX H   ;INCREASE ADDRESS POINTER

23 1016 7D        MOV A,L   ;COMPARE LOW MEMORY POINTER TO GOAL

24 1017 FE00      CPI LOWADDR

25 1019 C20B10    JNZ LOADLP    ;NOT EQUAL, CONTINUE

26 101C 7C        MOV A,H   ;COMPARE HIGH MEMORY POINTER TO GOAL

27 101D FE03      CPI HIGHADDR

28 101F C20B10    JNZ LOADLP    ;NOT EQUAL, CONTINUE

29 1022          ;*******************************

30 1022          ;* The memory image has been downloaded.  You can choose between two

31 1022          ;* next steps.  One is to jump right to address 0000 and start running

32 1022          ;* the image.  The second is to halt the computer.  If you choose halt

33 1022          ;* you will have to reset the Altair, examine address 0000, and then

34 1022          ;* press run to boot basic

35 1022          ;*******************************

36 1022          ;  JMP H'0000    ;MEMORY IMAGE DOWNLOADED, JMP to 0000

37 1022 76        HLT

38 1023          ;

CONT    =0000  

DATA    =0001  

HIGHADDR=0003  

LOADLP  =100B  

LOWADDR =0000  

RESET   =1000