ISA bus PWM and Quadrature Encoder Circuit
Specification Document


Note: Project dropped as it was to large for the CPLD devices I could program at the time.  I may revive it in the future.
The idea is to make a circuit that can be programmed into a FPGA and used.


Pinout of FPGA
 
Signal
Group
Signal Name Dir Lvl # Pin Description
ISA AEN I 1 Must be low for IO operation
ISA BALE I 1 I think I can ignore this one.
ISA CLK I 1 ISA bus clock, assign to one of the global clocks.
ISA SA(15:0) I 16 System addresses used for IO operations.  Should check all so I can use the extended IO address space.
ISA -IO CS 16 O 1 Tells the system we are a 16 pit device.  Drive it low as soon as we have an address match.
ISA -IO CH CK O 1 NMI to system if the device has an uncorectable error.  Not likely to be used.
ISA -IOR I 1 Read strobe line for IO operation.
ISA -IOW I 1 Write stobe line for IO operation.
ISA SD(15:0) I/O 16 Data Bus
ISA I/O CH RDY O 1 Allows us to extend the bus cycle.  Not likely needed.
ISA IRQ O 1 Interupt ouput pin.  Use a jumper to tie it to one of the system IRQ lines.
ISA OSC I 1 System oscilator.  Assign to one of the global clock pins.
ISA RESET DRV I 1 Reset input from the system.
ISA -SBHE I 1 System high Byte Enable tells us the system is putting data on the (15:8) data pins.
Motor A MA-PWM O 1 PWM output for motor A.
Motor A MA-Direction O 1 Direction output for motor A.
Motor A MA-Brake O 1 Brake output for motor A.
Motor A MA-Thermal I 1 Thermal input frlag from motor A.
Quad A QA-CH-A I 1 Quadrature channel A input for motor A.
Quad A QA-CH-B I 1 Quadrature channel B input for motor A.
Motor B MB-PWM O 1 PWM output for motor B.
Motor B MB-Direction O 1 Direction output for motor B.
Motor B MB-Brake O 1 Brake output for motor B.
Motor B MB-Thermal I 1 Thermal input frlag from motor B.
Quad B QB-CH-A I 1 Quadrature channel A input for motor B.
Quad B QB-CH-B I 1 Quadrature channel B input for motor B.
MISC 50MHz I 1 Attach to one of the global clock lines.  This will be the refference clock for PWM gneration.
MISC LED(7:0) O 8 LED ouputs for status indicators.
MISC Local Reset I 1 Local on the board reset input.
MISC All Stop I 1 All stop signal.  When grounded coses a shutdown of the PWM systems.
Total 67 8 not needed.


Externally Visible Registers
 
Name Data type Initial Value Description
PWM A Length Unsigned Integer (0-2046) 0


Internal Registers
 
Name Data Type Initial Value Description


Internal Signals
 
Name Data Type Initial Value or Source Description


© Copyright 2000-2001, Bryan Andersen