CHAPTER 3 HARDWARE SETTINGS AND FUNCTIONS
User’s Manual U17029EJ3V0UM
37
3.8 Cautions on Creating Target System
Be sure to note the following cautions when creating the target system.
•
Do not place X1 and X2 next to each other on the target board. If the layout requires this, they should be made
as short as possible.
•
Make the distance to the target connector as short as possible.
•
Since the X1 and X2 lines are used for clock supply, be sure to shield them, such as with a GND pattern.
•
Before shipping the product, use jumpers or other means to physically separate the X1 and X2 pins from the
target connector in order to ensure normal clock oscillation.
•
When debugging, remove capacitors, feedback resistors, and other elements for the resonator in order to
prevent signal degradation due to the load placed on the X1 and X2 pins.
Figure 3-9. Reference Example of Target System
Target chip
X1
X2
Make the pattern where X1 and X2 are next to each other
as short as possible, or make the space wider
Connect to the connector by using tin plating
when debugging
Shield both sides of the line to reduce noise
To debug connector
GND pattern
