Specifications

106 Intel
®
Atom™ processor CE4100 Ref# 420826
Platform Design Guide
Intel Confidential
8.4.3 Data Bus A
EXP_DATA_A and EXP_DATA_B, EXP_DATA_A is intended for access to “insecure” devices,
and no special measures are taken to prevent the access to its lines on the PCB. For
instance, this bus may be used to communicate with the boot PROM or any other external
flash devices, LEDs, front panel controls.
Figure 8-18. Data Bus DA<0-7> Topology
Table 8-10. Data Bus_A Topology list
Traces Layer Min Length
Max
Length
Trace:
Width/Spacing
Spacing from other
signals
w_TL0
Breakout
0.1” 0.5” 4 mils >=4 mils
w_TL1+w_TL2
Micro strip
0.1” 2.5” 4 mils >=8 mils
w_TL3
Micro strip
0.1” 0.5” 4 mils >=8 mils
w_TL4/5/6/7
Micro strip
0.1” 1” 4 mils >=8 mils
Notes:
• Match all signals within 0.2”.
• All trace impedance required to be 55 Ω +/- 10%.
• All signals should be referenced to ground. Reference to unbroken power plane is also accepted.