Hercules-EBX CPU User Manual V1.02
Page 37
Signal Name
Definition
+5V
Main +5V Power supply on Hercules-EBX board
+3.3V
Main +3.3V Power supply on Hercules-EBX board
PCI VIO
“V I/O” pins on J3
5 3
J19
PCI VIO
Set to 5V
5 3
J19
PCI VIO
Set to 3.3V
5 3
J19
PCI VIO
No Setting - No
power (BAD)
Figure 8 : Possible VIO Settings for J19
PC/104+ cards are supposed to be keyed to identify the correct voltage setting – no key is
supposed to mean that the card is universal and can accept either power setting. There are
essentially 4 possibilities:
1) Card keyed for 5V
2) Card keyed for 3.3V
3) Card not keyed – universal (can operate with either voltage setting)
4) Card incorrectly keyed or not keyed but with certain requirements
The first three possibilities can be easily determined by checking the keying of the card:
•
5V card = Pin A1 missing / pin D30 present
•
3.3V Card = Pin A1 present / pin D30 missing
•
Universal Card = both pins present
The only solution for cards that are incorrectly keyed is to read the documentation and verify the
I/O voltage (if it is called out in the card description). While not a widespread issue, this is
something to be aware of when starting to work with a new PC/104+ card.
See pages 12 and 119 for details on the PC/104+ Connector and PC/104+ cards. Note that this
voltage selection is not used for standard PC/104 cards; only the PCI-signaling of PC/104+.
5.4 J33: Data Acquisition Calibration Test Points
Jumper block J33 is used for measuring internal Analog Data Acquisition voltages to ensure
precise calibration. For most applications, these test points will not be of use.
If you require access to these internal voltages, here is a listing of the signals present on this
header:
J33
Pins 1 3 5 7 9
