The "P4X 040 system" is a 6U VMEbus board build around the Motorola MC68040 microprocessor.

It is ideal for high-end embedded real-time monitor, control and server applications. The usage of the MC68EN360 QUICC as intelligent multiple IO controller provides a large offering of interfaces: Ethernet, parallel port, three serial ports configurable as RS232, RS422, second ethernet or Profibus. The VMEbus interface uses the VIC068A gate array to provide a complete state of the art backplane transmission media. Mass storage devices can be handled by the onboard intelligent fast SCSI-2 controller. A key feature of the P4X is its double local bus structure which permits to each component to work at its optimum throughput level.

The combination of the high performance MC68040 and the IO versatility of the QUICC puts low cost features into a high performance single board VMEbus computer.



 VMEbus Interface

The "P4X 040 system" VMEbus interface has been optimized for operation in a multiprocessor environment. By using the VIC068A gate array, more than just the standard VMEbus functions are supported. One of these additional features is the message passing mechanism which allows together with the main memory slave capability the efficient implementation of multiprocessor systems.

The VIC068A chip supports all standard data transfer modes of the VMEbus as master and slave interface. Additionally 32 bit block transfer is supported. The write posting feature provides a major relief of the cpu or the bus master. Data that has to be transferred via the VMEbus is buffered in fast latches and, afterwards, transferred without any further interaction of the cpu - any unnecessary cpu cycles are avoided.

The "P4X 040 system" has a software configurable VMEbus interrupter and interrupt handler module. The following parameters may be selected : priority of an interrupt request, and the number and priority of any interrupt request to be handled. This way every possible interrupt structure may be applied, either a distributed or a central interrupt system.

The board is able to assume all functions of a VMEbus system controller : generation of the system clock, reset function, watchdog timer, iack daisy chain driver, and four level arbitration (single level, priority, round robin).

Peripheral Interfaces

The 8 bit fast SCSI interface may be used to connect up to seven mass storage devices (hard disks, optical disks tapes, and floppy disks). The bus is controlled by the 53C710 chip. The risk kernel contained in this component allows hardware independent programming by the SCSI SCRIPT language. The cpu load gets reduced, since the 53C710 relieves it from controlling the SCSIbus protocol. 

The communication channels are implemented using the Motorola MC68EN360 / QUICC controller chip.

The QUICC delivers the ethernet / IEEE 802.3 protocol on the first SCC channel. An external manchester encoder is installed on the board.

The "P4X 040 system" offers two different network media interfaces :

The P4X has three serial ports which may configured with different line driver types by means of a serial piggyback module.

 Actually five piggyback options are available :

first channel (SCC2) second channel (SCC3) third channel (SCC4) designation
RS232 profibus (isolated RS485) - P4XSP1
RS232 RS232 - P4XSP2 RS232 option
RS232 RS422 - P4XSP2 RS422 option
RS232 RS232 Second Ethernet AUI P4XSP3
RS232 RS232 RS232 P4XSP4


The standard delivery is with two RS232 ports installed.

In order to connect a printer, a centronics compatible parallel interface is provided.

The local asynchronous bus is routed to the mezzanine board expansion connector.

An M-module carrier board can be plugged into this slot to permit the construction of compact controller systems without loading the VMEbus.

Manufacturing quality

 The SimTech products are manufactured using high quality components. Each board is submitted to a 12 hours burn in.

 Technical specifications

 Main processor

 Main memory

IO processor

Static RAM

Flash memory

Boot eprom


Designation type bit capacity byte capacity
27C010 EPROM 1 M 128 K
27C020 EPROM 2 M 256 K
27C040 EPROM 4 M 512 K
29F010 5 V FLASH 1 M 128 K
29F040 5 V FLASH 4 M 512 K


 VMEbus (IEEE STD 1014)



Counters / Timers

Watchdog Timers

 Asynchronous serial ports

 Profibus port

Parallel Port

Mezzanine Card Slot

Board Size

Power Requirements

other frontpanel elements

Backpanel elements (on P4XBP)



Ordering information

1. P4X base board :

standard configurations :

- 040 CPU

- QUICC in slave mode

- 128K boot eprom

- SCSI Interface

- VMEbus Interface

- no SRAM

- no Flash

- EDO DRAM without parity


cpu type cpu speed DRAM size SRAM size Flash size ordering code
MC68040 40 MHz 4 Mbyte 0 0 P4X_040_40_4_0_0
MC68040 40 MHz 8 Mbyte 0 0 P4X_040_40_8_0_0
MC68040 40 MHz 16 Mbyte 0 0 P4X_040_40_16_0_0
MC68040 40 MHz 32 Mbyte 0 0 P4X_040_40_32_0_0


other options on request :

2. P4X serial piggyback

standard configuration :

P4XSP2 RS232 option

other options on request :

first channel (SCC2) second channel (SCC3) third channel (SCC4) designation
RS232 profibus (isolated RS485) - P4XSP1
RS232 RS232 - P4XSP2 RS232 option
RS232 RS422 - P4XSP2 RS422 option
RS232 RS232 Second Ethernet AUI P4XSP3
RS232 RS232 RS232 P4XSP4

Data sheet revision : 1.2