32171 Datasheet, PDF (673/772 Pages) Renesas Technology Corp – 32-BIT RISC SINGLE-CHIP MICROCOMPUTER M32R FAMILY / M32R/ECU SERIES

19
JTAG
19.6 Precautions on Board Design when Using JTAG
19.6 Precautions on Board Design when Using JTAG
The JTAG pins require that wiring lengths be matched during board design in order to accomplish
fast, highly reliable communication with JTAG tools.
An example of how to process pins when using JTAG tools is shown below.
M32R/ECU
JTDO
JTDI
JTMS
JTCK
JTRST
VCCE(5V) ^{SDI connector (JTAG connector)}
10KΩ
33Ω
10KΩ
33Ω
10KΩ
33Ω
10KΩ
33Ω
Power
TDO
TDI
TMS
TCK
33Ω
2KΩ
0.1µF
TRST
GND
User board
JTAG tool
Make sure wiring lengths are the same, and avoid bending wires
as much as possible. Also, do not use through-holes within wiring.
Notes: •Only if the JTRST pin is firmly tied to ground, it dosn’t matter whether the JTDO, JTDI, JTMS, and
JTCK pins are pulled high or pulled low.
• Even when not using JTAG tools, always be sure to process each pin. The same pulldown/pullup
resistance values as when using JTAG tools may be used without causing any problem.
Figure 19.6.1 Example for Processing Pins when Using JTAG Tools
19-15
32171 Group User's Manual (Rev.2.00)