i am sorry, i am new to asm, to get the software uart, i compiled my c to generate asm, and just inserted the software uart asm and shown below.


thanks in advance

d9600 equ 48
nfbit equ d9600
nhbit equ d9600/2
nqbit equ d9600/4 ; 1/4
ntbit equ nhbit + nqbit ; 3/4

putc: push 1
push 6
push 7
CLR TPIN ;Drop line for start bit
call fulbit
MOV R1,#8 ;Send 8 bits
putc1: RRC A ;Move next bit into carry
MOV TPIN,C ;Write next bit
call fulbit
djnz r1,putc1
SETB TPIN ;Set line high for stop bit
rrc a
call fulbit
pop 7
pop 6
pop 1
RET



tfhbit: mov r6,#low Ntbit
mov r7,#high Ntbit or 1 ; at least 1
sjmp hofb
hafbit: mov r6,#low Nhbit
mov r7,#high Nhbit or 1 ; at least 1
sjmp hofb
fulbit: mov r6,#low Nfbit ; 1
mov r7,#high Nfbit or 1 ; at least 1
hofb: djnz r6,hofb ; 2
djnz r7,hofb ; 2 ; if 1 then exit
nobit: ret ; 2