The front panel data port (FPDP) is a bus that provides high speed data transfer between two or more VMEbus

VMEbus

VMEbus is a computer bus standard, originally developed for the Motorola 68000 line of CPUs, but later widely used for many applications and standardized by the IEC as ANSI/IEEE 1014-1987. It is physically based on Eurocard sizes, mechanicals and connectors , but uses its own signalling system,...

 boards at up to 160 MB/sec with low latency. The FPDP bus uses a 32-bit

32-bit

The range of integer values that can be stored in 32 bits is 0 through 4,294,967,295. Hence, a processor with 32-bit memory addresses can directly access 4 GB of byte-addressable memory....

 parallel synchronous bus wired with a 80-conductor ribbon cable

Ribbon cable

A ribbon cable is a cable with many conducting wires running parallel to each other on the same flat plane. As a result the cable is wide and flat. Its name comes from the resemblance of the cable to a piece of ribbon.Ribbon cables are usually seen for internal peripherals in computers, such as...

.

The following interface functions are supported:

• FPDP/TM (transmitter master) - drives data and timing signals
  Clock signal
  In electronics and especially synchronous digital circuits, a clock signal is a particular type of signal that oscillates between a high and a low state and is utilized like a metronome to coordinate actions of circuits...
  
   onto the FPDP, and also terminates the bus signals at one end of the ribbon cable
• FPDP/RM (receiver master) - receives data from the FPDP synchronously
  Synchronization
  Synchronization is timekeeping which requires the coordination of events to operate a system in unison. The familiar conductor of an orchestra serves to keep the orchestra in time....
  
   with the timing signals provided by the FPDP/TM, and also terminates the bus at the opposite end of the cable to the FPDP/TM
• FPDP/R (receiver) - receives data form the FPDP synchronously with the timing signals provided by the FPDP/TM; it does not terminate the bus. More than one FPDP/R can be connected to the FPDP bus. It can also be an alternate function to that of FPDP/RM via software control.

The connector, denoted by the FPDP specification, is a KEL P/N 8825E-080-175.

Interface signals

• D<31:0> : Data bus driven by FPDP/TM
• DIR_n : Active low Direction signal driven by FPDP/TM
• DVALID_n: Active low data valid indication driven by FPDP/TM
• STROBE : A free running clock supplied by FPDP/TM
• NRDY_n : Active low not ready signal driven by FPDP/R or FPDP/RM. Asserted before the commencement of transfer of data by the FPDP/R or FPDP/RM asynchronous to STROBE.
• PSTROBE : Optional Differential PECL version of the STROBE driven by FPDP/TM
• SUSPEND_n : Active low suspend signal asserted by FPDP/R or FPDP/RM asynchronous to STROBE to inform the transmitter that buffer flow condition may occur. The transmitter may delay not more than 16 clocks before it suspends the data transfer.
• SYNC_n : Active low synchronization pulse provided by FPDP/TM.
• PIO1, PIO2 : Programmable I/O lines for user purposes

Data frames

The following types of data frames are supported:

• Unframed Data
• single frame Data
• Fixed size Repeating Frame Data
• Dynamic Size Repeating Frame Data

Cable length

FPDP interfaces work with up to a cable length of 1 meter when used in multi-drop configuration. They work up to 2 meter when using STROBE signal during point-to-point configuration. They work up to 5 meter when used with PSTROBE differential signal during point-to-point configuration.

See also

• VMEbus
  VMEbus
  VMEbus is a computer bus standard, originally developed for the Motorola 68000 line of CPUs, but later widely used for many applications and standardized by the IEC as ANSI/IEEE 1014-1987. It is physically based on Eurocard sizes, mechanicals and connectors , but uses its own signalling system,...
  
   - a computer bus standard widely used for many applications and standardized by the IEC as ANSI/IEEE 1014-1987
• Fiber FPDP
  Serial FPDP
  Serial Front Panel Data Port is a high speed low latency data streaming serial communication protocol. It currently supports three distinct speeds, 1.0625 Gbit/s, 2.125 Gbit/s, 2.5 Gbit/s. Serial FPDP can operate over long distances, up to , using optical fiber cables....
  
  - Fiber version of the FPDP used with VXI.