Tap Controller - Freescale Semiconductor MPC850 User Manual

TAP Controller

The MPC850 TAP logic is shown in Figure 45-1 below.
TDI
TRST
TMS
TCK
45.2 TAP Controller
The TAP controller is responsible for interpreting the sequence of logical values on the
TMS signal. It is a synchronous state machine that controls the operation of the JTAG logic.
The value shown adjacent to each bubble represents the value of the TMS signal sampled
on the rising edge of TCK. Figure 45-2 shows the MPC850 TAP controller state machine.
BOUNDARY SCAN REGISTER
BYPASS
INSTRUCTION APPLY & DECODE REGISTER
3 2 1
4—BIT INSTRUCTION REGISTER
TAP CONTROLLER
Figure 45-1. Test Logic Block Diagram
MPC850 Family User's Manual
M
U
X
0
M
U
X
TDO