DS1307读写程序.doc

scl bit p3.4sda bit p3.5cmdw equ 11010000bcmdr equ 11010001borg 00hajmp beginorg 0030hbegin:mov sp,#70hmov 95h,#00hmov 96h,#0ffhmov r4,#8mov r1,#30hlcall read_mb;多字节写mov a,30hjnb acc.7,re1;csh:lcall init;初始化mov r2,#00hmov r4,#8mov r1,#30hlcall write_mb;多字节写clr p3.1re1:mov r4,#8mov r1,#30hlcall read_mb;多字节写mov a,30hmov p2,aajmp re1sjmp beginwrite_mb:;lcall start_bit;mov a,#cmdw;mov r7,#8lcall shftolcall slave_ack;从应答mov a,#00;r2mov r7,#8lcall shftolcall slave_ack;从应答write_mbo:;mov a,r1mov r7,#8lcall shftolcall slave_ack;inc r1djnz r4,write_mbo;lcall stop_bit;retread_mb:;lcall start_bit;mov a,#cmdwmov r7,#8lcall shfto;lcall slave_ack;mov a,#0mov r7,#8lcall shfto;lcall slave_ack;lcall start_bit;mov a,#cmdrmov r7,#8lcall shfto;lcall slave_ack;read_mb0:mov r7,#8;lcall getfrom;lcall matr_ack;lcall slave_ackmov r1,ainc r1djnz r4,read_mb0;lcall no_acklcall stop_bitretstart_bit:setb sclnopsetb sdanopclr sdanopclr sclretstop_bit:clr sdanopsetb sclnopsetb sdaretshfto:clr sclshfto_0:clr sclrlc amov sda,csetb scldjnz r7,shfto_0retgetfrom:setb sclnopmov c,sdaclr sclrlc adjnz r7,getfrom;retslave_ack:;nopnopclr sclnopsetb sdanopnopsetb sclnopnopmov c,sdaclr sclretno_ack:setb sdanopsetb sclnopclr sclretinit:mov r1,#30hmov r4,#8init0:mov r1,#00hinc r1djnz r4,init0mov 37h,#90hretm