HEATH ASM #104.06.00 20-Sep-21 Page 1 00001 * 42-byte bootstrap loader with initialization for 8250 00002 * originally written for H89 but code-compatible with 00003 * H8 with H-8-4 00004 00005 * 00006 * Use "LP" com port 00007 * 000.340 00008 LP EQU 340Q 000.340 00009 RX EQU LP 000.340 00010 DVL EQU LP 000.341 00011 DVH EQU LP+1 000.341 00012 IER EQU LP+1 000.343 00013 LCNTL EQU LP+3 000.344 00014 MCNTL EQU LP+4 000.345 00015 LSTAT EQU LP+5 00016 046.133 00017 DBEND EQU 265BH From H89LDR.PRN 00018 043.000 00019 ORG 043000A 00020 043.000 257 00021 LDR XRA A 043.001 323 343 00022 OUT LCNTL Line control 043.003 323 341 00023 OUT IER No interrupts please 043.005 323 344 00024 OUT MCNTL Initialize modem control 043.007 075 00025 DCR A Should be 'MVI A, 80H' but 0FFH OK 043.010 323 343 00026 OUT LCNTL 043.012 076 014 00027 MVI A,0CH 9600 BAUD 043.014 323 340 00028 OUT DVL 043.016 257 00029 XRA A 043.017 323 341 00030 OUT DVH 043.021 076 007 00031 MVI A,07H 8 bits 2 STOPS 043.023 323 343 00032 OUT LCNTL This will be 2313, Must NOT be 0FAH 043.025 333 345 00033 IN LSTAT 043.027 333 340 00034 IN RX Clear any junk 043.031 041 037 043 00035 LXI H,LDR1 043.034 021 132 046 00036 LXI D,DBEND-1 Depends on size (to be determined) 043.037 333 345 00037 LDR1 IN LSTAT 043.041 037 00038 RAR 043.042 322 037 043 00039 JNC LDR1 Wait for char 043.045 333 340 00040 IN RX 043.047 022 00041 STAX D 043.050 033 00042 DCX D 043.051 351 00043 PCHL To be overwritten by loader w/ NOP 00044 * 00045 * '*' should be 043051A 00046 * 043.052 000 00047 END LDR 00047 Statements Assembled 38696 Bytes Free No Errors Detected