5
PMCCTR32
Copyright
2001 BVM Ltd.
3.3 Main
Logic
The PMCCTR32 uses a Xilinx SpartanXL FPGA connected to the 16-bit local bus to provide the on-
board logic functions as described below.
3.3.1
Counter/Timer Output Register
An 8-bit Counter/Timer Output Register containing the levels of the Counter/Timer Output pins on the
logic device.
3.3.2
Counter/Timer Clock Register
An 8-bit Counter/Timer Clock Register containing the level of the Counter/Timer Clock Input pins on
the logic device.
3.3.3
Counter/Timer Gate Register
An 8-bit Counter/Timer Gate Register containing the level of the Counter/Timer Gate Input pins on the
logic device.
3.3.4
Counter/Timer Direction Register
An 8-bit Counter/Timer Direction Register containing the level of the Counter/Timer Direction Input
pins on the logic device.
3.3.5
Counter/Timer Gate Override Register
An 8-bit Counter/Timer Gate Override Register where each bit is OR'ed with the corresponding gate
input pin for the respective Counter/Timer.
3.3.6
Counter/Timer Direction Override Register
An 8-bit Counter/Timer Direction Override Register where each bit is OR'ed with the corresponding
direction input pin for the respective Counter/Timer.
3.3.7
Counter/Timer Status Register
An 8-bit Counter/Timer Status Register where each bit indicates that the Counter/Timer output is
active.
3.3.8
Counter/Timer Output Control Register
An 8-bit Counter/Timer Output Control Register where each bit is used to select the polarity of the
Counter/Timer output.
3.3.9
Counter/Timer Interrupt Enable Register
An 8-bit Counter/Timer Interrupt Enable Register where each bit is used to enable the interrupt for the
Counter/Timer.
3.3.10 Counter/Timer Clock Source Register
An 8-bit Counter/Timer Clock Source Register where each bit is used to select the internal or external
clock for the Counter/Timer source.
3.3.11 Direction
Register
An 8-bit Direction Register where each bit corresponds to a group of 8 I/O bits. If the corresponding bit
is set to 1 output is enabled otherwise input is enabled.
3.3.12 Function
Register
An 8-bit Function Register which contains the low byte of the PCI Subsystem Device ID - used to
determine the type of board fitted from the PMCDIO and PMCCTR range.
