Your delay routine is weird, and probably is not what you expect from it

void DelayMS(unsigned int ms) {
        ms;
        _asm
        mov     r0, dpl
00001$: mov     r1, #230
00002$: nop
        nop
        nop
        nop
        nop
        nop
        djnz    r1, 00002$
        djnz    r0, 00001$
        ret

You give an integer (speed=8000) to it, but how is this 2 byte parameter used in the routine ? You only say: ms; (?). I don't see why DPL is used in the routine as a delay parameter (and NOT ms).

You should see to which 2 registers is an integer variable copied, and then use them to construct a similar delay loop.

Regards, Slobodan