Design notes for Rvalve board
Created: 08-Mar-04 SJensen  

14-May-04 SJensen
	Updated schematic with changed values and new parts.  The 0201 resisitors will be soldered across the transitor leads.  PolyFuses are changed to Fuses, 2.5A
	   
15-Apr-04 JRosal
	Added footprints to new components.
	
14-Apr-04 SJensen
    Created Rev 0 0 3
    
    Due to size and layout changes, u6 and 15 were changed to 74hct541 for better pin layout.   
    
    Changed from BAT400 to BAS40.  This is a dual diode instead of a single.  Also to reduce size
    
 07-Apr-04 SJensen
    Removed the Differential amps and connector for the pressure and temperature senors - these functions
    are moving to a sensor board since the temperature will be a type K thermocouple.
    
31-Mar-04 JRosal
	Changed NET connection order to U4
26-Mar-04 JRosal
    Changed PINOUT of J5 to fix PCB routing complications. (16-19, 14-17, 12-15, 10-13)

24-Mar-04 JRosal
	Changed NET connection order of U4 pins that attach to page 2 schematic
	
23-Mar-04 SJensen
   Added the offset amplifier for the pressure sensor.
    
20-Mar-04 SJensen
	Added the items below...
	   
19-Mar-04 SJensen
	Need to add termination resistors to the in's from encoderes.  Use the same as the dwarf bus terminators.
	
	Need to add source termination to the encoder clocks
	
18-Mar-04 SJensen
  Made a few changes to send pressure and temps to MSP.  
  Removed GIO0,1,2 for use as selection jumpers
  fixed CPLd programming jumper to leave MSP_RST open.
  
15-Mar-04 SJensen
  Prepaired package to hand off for layout. 
  
  need to decide on current sense resistor.  Have a possibility on order.

09-Mar-04 SJensen
  The valve h-bridges should support 1 amp of continuous current.
  
  The CPLD should be able to support 8 valves.  May need to loose some of the switches.      
  
  Change 74HCT244M to a 74HCT244PW -  This a TSSOP and half the size.
  
  consider using MAX4372TEUK this is SOT23-5
  
  Change 74HC4051M to MM74HC4051MTC from Fairchild
  
  Loose some of the GPIO from the bus in favor of a jumper or two.
  
08-Mar-04 SJensen
  This boards function is to drive up to 4 of the rotary valves.  It will be using the same H-bridge as the servo drives.
  To save future space I should try to fit up to 8 valve drives on this and possibly 16.