Sequencer board.
- An Altera Avalon switch-fabric making up the backbone of the controller.
- Complete MPU ( Altera NiosII softprocessor,16MB SDRAM, 8MB flash ), assisting in setting up all voltages and tables during power up, decoding commands and requests sent to the controller via the fiber interface, and handling the local hardware communication acknowledge correspondingly.
- Custom designed sequencer, programmed and controlled by the local MPU. The sequencer generates controls for the clock drivers, cds, data conversion and data handling with 10ns time resolution. A part of the sequencer is a timer, keeping track of integration times. Start/stop operations are calculated by hardware ensuring that timing errors are not accumulated, even during multiple hold/resume sequences.
- OptoRing module.
- Serial I/O to support interface to temperature controller, GPS, shutter interface etc
- Syncronization. The
sequencer is able to operate as a
master, syncronizing other controllers and their power supplies, or, -
as a
slave that syncronizes to external sources f.ex. other controllers or
timing
sources ( GPS etc). This mechanism syncronizes the sequencer operation
(
shutter, exposure, readout) down to a single clock, effectively keeping
jitter between multiple controllers below 10ns.
Figur
5: Sequencer board, containing complete 32bit RISC processor,
sequencer,
OptoRing-fiber-communication, syncronization and optocoupled interface
with
temperature- and shutter-controllers.
External to the fpga are:
- Memory. SDRAM and flash memory for configuration and MPU code and setup data
- Fiber interface modules,
- System connector for interface with analog boards( clock and video ) ,
and optionally -
- Connectors for external syncronisation
- Optoisolators for the Serial/shutter interface
- Connector for interface to direct dewar LED control, telemetry data ect.
Collecting all digital hardware, including the
MPU, inside a fpga, makes it possible to make remote updates of
hardware configuration and software.