var loop = E.asm("void()",`
ldr r2, port_A //Load port_A in r2
movw r3, #57344 //Load mask in r3
str r3, [r2, #0] //Set is r2
str r3, [r2, #4] //Clear is r2+4
It takes 223 ns to loop once, but three cpu cycles @72MHz are 3*1e9*1/72e6= 41.6 ns, can I touch some clock setting somewhere to make it toggle faster?