PT-VME940 VMEBus Adapter

GENERAL DESCRIPTION
Model PT-VME940 is the VMEbus Adapter for a high speed data communications network utilizing a multi-drop parallel interconnect bus and multiple twisted pair cable.

The PT-VME940 features a VME64 Master interface to achieve VMEbus transfer rates up to 60 Mbytes/second.

MECHANICAL AND ENVIRONMENTAL SPECIFICATIONS

                               
                                                                                 
 Characteristic                         Specification                             
                                                                                 
 Power Requirements                    Model PT-VME940-T                          
                                       +5V  (+/-5%)  @ 4.5  Amps typical          
                                                    @ 5.2 Amps maximum            
                                                                                 
                                       Model PT-VME940-U                          
                                       +5V  (+/-5%)  @ 4.0  imps typical          
                                                    @ 4.7 Amps maximum            
                                                                                 
                                       +12V (+/-5%) @ 15ma maximum                
                                                                                 
                                       -12V (+/-5%) @ 15ma maximum                
                                                                                 
 Ambient Temperature                   0' to +55' C, operating                    
                                       -55' to +85' C, storage                    
                                                                                 
 Humidity                              0% to 90% (non-condensing)                 
                                                                                 
 Physical                              Double-width VME Eurocard:                 
                                                                                 
                                        Width             234mm (9.2in)           
                                        Depth             160mm (6.3in)           
                                        Comp  Height      13.5mm (.54in) Max.     
                                        Front  Panel      20.3mm (0.8in)          
                                                                                 
 HARDWARE SPECIFICATIONS                                                          
                                                                                 
 Characteristic                         Specification                             
                                                                                 
 Processor                              68020 0 12.5 Mhz.                         
 Program Store Memory                   Static RAM                                
                                        128K Bytes                                
                                        0 Wait State Performance                  
                                                                                 
 VMEbus Transfer Rate                   60 Mbytes/second                          

 Cable Transfer Rate      40 Mbytes/second     
                                              
 VMEbus Master Interface  A32/A24:D64/D32 BLT
                         A32/A24:D32/D16/D8(EO)
 Maximum Number Of Nodes  16                   
 Maximum Length Of Cable  100 feet           

STATIC RAM
Four byte-wide static RAMs are provided for use as a 32 bit wide program store. Standard configuration provides four 32Kx8 120nsec SRAMs which allow 0 Wait State performance at 12.5 Mhz. In operation, application firmware is moved from the EPROM to the SRAM after power up/initialization and is executed from SRAM.

PROCESSOR
The PT-VME940 is equipped with a 12.5 Mhz MC68020 32 bit microprocessor.

EPROM
The PT-VME940 is equipped with a standard 32 pin JEDEC EPROM socket. The EPROM is accessed as a byte port and is used as a storage device for the application code used to manage the network protocol.

MULTI-FUNCTION PERIPHERAL
Utility functions on the PT-VME940 are provided by a 68901 Multi-Function Peripheral. This device provides the hardware support for the serial Debug Port as well as timers and I/O lines used internally.

VME64 MASTER INTERFACE
The heart of the VME64 interface is a 64-bit wide by 1024 stage bi-directional FIFO. This FIFO effectively decouples the network cable transfer rate from the VMEbus transfer rate and allows maximum size VME64 blocks to be sent/received at speeds limited primarily by the capability of the slave.

The VME64 interface is implemented using an asynchronous state machine utilizing special design techniques to minimize susceptibility to the backplane signal quality degradations commonly seen with high backplane repetition rates.

CABLE INTERFACE
The cable interface is managed by a synchronous state machine and is connected to the VME64 Interface FIFO.

VMEbus SLAVE INTERFACE (VSI) The VSI is a PTI proprietary ASIC which forms the core of the VMEbus slave interface. The VSI decodes the PT-VME940's slave address by monitoring the VMEbus for a preset address. The VSI provides 16 dual-ported mailbox registers which interrupt the on-board 68020 when they are accessed from the VMEbus. These registers are used to implement the CSB. The VSI also implements the VMEbus interrupter with fully programmable level and vector number.