Motorola MVME197LE user manual Printer Interface, Ethernet Interface

Functional Description

All four serial ports use EIA-232-D drivers and receivers located on the main board, and all the signal lines are routed to the I/O connector. The configuration headers are located on the MVME712X transition board. An external I/O transition board such as the MVME712X should be used to convert the I/O connector pinout to industry-standard connectors.

The interface provided by the PCCchip2 allows the 16-bit CD2401 to appear at

4contiguous addresses; however, accesses to the CD2401 must be 8 or 16 bits. 32-bit accesses are not permitted. Refer to the CD2401 data sheet and to the PCCchip2 chapter in the MVME197LE, MVME197DP, and MVME197SP Single Board Computers Programmer’s Reference Guide for detailed programming information.

The CD2401 supports DMA operations to local memory. Because the CD2401 does not support a retry operation necessary to break VMEbus lock conditions, the CD2401 DMA controllers should not be programmed to access the VMEbus. The hardware does not restrict the CD2401 to onboard DRAM.

Printer Interface

The MVME197LE has a Centronics-compatible printer interface. The printer interface is provided by the PCCchip2. Refer to the PCCchip2 chapter in the MVME197LE, MVME197DP, and MVME197SP Single Board Computers Programmer’s Reference Guide for detailed programming information and for drawings of the printer port interface connections.

Ethernet Interface

The 82596CA is used to implement the Ethernet transceiver interface. The 82596CA accesses local RAM using DMA operations to perform its normal functions. Because the 82596CA has small internal buffers and the VMEbus has an undefined latency period, buffer overrun may occur if the DMA is programmed to access the VMEbus. Therefore, the 82596CA should not be programmed to access the VMEbus.

Every MVME197LE module is assigned an Ethernet Station Address. This address is $08003E2XXXXX, where XXXXX is the unique 5-nibble number assigned to the board (i.e., every MVME197LE has a different value for XXXXX).

The Ethernet Station Address is displayed on a label attached to the VMEbus P2 connector. In addition, the eight bytes including the Ethernet address are stored in the configuration area of the BBRAM, with the two lower bytes of those set to 0. That is, 08003E2XXXXX0000 is stored in the BBRAM. At an address of $FFFC1F2C, the upper four bytes (08003E2X) can be read. At an address of $FFFC1F30, the lower four bytes (XXXX0000) can be read. Refer to

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