Maxim Integrated MAXQ610 - Manual (Page 150)

11-6
MAXQ610 User’s Guide
For the host to establish a specific data communication link, a private instruction must be loaded into the IR[2:0] reg-
ister . Once the instruction is latched in the instruction parallel buffer at the update-IR state, it is recognized by the TAP
controller and the communication channel is established . In-circuit debug or in-system programming commands and
data can be exchanged between the host and the MAXQ610 microcontroller by operating in the data register portion
of the state sequence (i .e ., DR-scan) . The TAP retains the private instruction that was loaded into IR[2:0] until a new
instruction is shifted in or until the TAP controller returns to the test-logic-reset state .
11.3.1 TAP Communication Examples—IR-Scan and DR-Scan
Figure 11-3 and Figure 11-4 illustrate examples of communication between the host JTAG controller and the TAP of the
MAXQ610 microcontroller . The host controls the TCK and TMS signals to move through the desired TAP states while
accessing the selected shift register through the TDI input and TDO output pair .
Figure 11-3. TAP Controller Debug Mode IR-Scan Example
NEW INSTRUCTION
INSTRUCTION REGISTER
TCK
TMS
TDI
TDO
CONTROL
STATE
IR SHIFT
REGISTER
IR PARALLEL
OUTPUT
REGISTER
SELECTED
TDO
ENABLE
BYPASS
DON'T CARE OR UNDEFINED DON'T CARE OR UNDEFINED
DON'T CARE OR UNDEFINED DON'T CARE OR UNDEFINED
TEST-LOGIC-RESET
RUN-TEST/IDLE SELECT-DR-SCAN SELECT-IR-SCAN
CAPTURE-IR
SHIFT-IR SHIFT-IR
EXIT1-IR EXIT1-IR
UPDATE-IR
RUN-TEST/IDLE
EXIT2-IR PAUSE-IR