MB2100-01A-E Single Port Embedded Emulator Debugger SPEED-BOX Operation Guide, Doc. # 002-05542 Rev. *A
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4.
User System Board Design Guidelines
The MDI bus of this product employs specifications that guarantee signal integrity by impedance
matching in order to achieve high-speed signal transmission over distances of 10m. There are
therefore rules on the method of wiring in the vicinity of the MCU MDI pin on the user system in order
to maintain signal quality. Design the user system board in accordance with the following rules.
4.1
Circuit board design rules
Figure 4-1 shows a schematic of the circuit near the MCU MDI pin. Specifications of the R0 value
depend on those of MCU. Also, there may be some MCU sharing MDI pin with other features. In this
case, to use this pin for MDI, it is necessary to prevent the circuit elements which is different from
one shown in this circuit from being added to the MDI bus. For details, refer to the Hardware Manual
for MCU you are using.
Figure 4-1. Schematic diagram of the circuit near the MCU MDI pin
MCU
MDI
(DEBUG I/F)
GND
R0
GND
GND
R1
Dz
L2
L1
User system
CN: MDI connector
MCU V
CC
