És un standard desenvolupat per el Joint Test Action Group , per simplificar la verificació de circuits impresos.

<mscgen caption="hola">

msc {

arcgradient = 8;
a [label="Client"],b [label="Server"];
a=>b [label="data1"];
a-xb [label="data2"];
a=>b [label="data3"];
a<=b [label="ack1, nack2"];
a=>b [label="data2", arcskip="1"];
|||;
a<=b [label="ack3"];
|||;

}

</mscgen>


Pinout JTAG
Senyal PIN PIN Senyal
TCK 1 2 GND
TDO 3 4 VccInt
TMS 5 6 IO2/OEGI
IO3/RTCK 7 8 VccIO
TDI 9 10 GND