TMS which will select different shift registers.
The first thing you need to do is reset the state machine, because when
-you connect to a chip you dont know what state the jtag is in,you need
+you connect to a chip you do not know what state the controller is in,you need
to clock TMS as 1, at least 7 times. This will put you into "Test Logic
Reset" State. Knowing this, you can, once reset, then track what each
-transition on TMS will do, and hence know what state the jtag state
+transition on TMS will do, and hence know what state the JTAG state
machine is in.
There are 2 "types" of shift registers. The Instruction shift register
For example, one of the data registers will be known as "bypass" this is
(usually) a single bit which has no function and is used to bypass the
-chip. Eg, assume we have 3 identical chips, wired up like the picture
+chip. Assume we have 3 identical chips, wired up like the picture
and each has a 3 bit instruction register, and there are 2 known
instructions (110 = bypass, 010 = some other function) if we want to use
"some other function", on the second chip in the line, and not change
0 1 0 1 0 1 1 1 1 0
-Again, we are clocking the lsbit first. Then we would clock TMS:
+Again, we are clocking the least-significant bit first. Then we would
+clock TMS:
1 1 0