DS200CTBAG1ADD通用模块,GE使用产品
PCCchip2提供的接口允许16位CD2401出现在连续地址；然而，对CD2401的访问必须是8位或16位。不允许32位访问。请参阅CD2401数据表和MVME197LE、MVME197DP和MVME197SP Single中的PCCCip2章板机程序员详细编程参考指南信息
CD2401支持对本地内存的DMA操作。因为CD2401不支持中断VMEbus锁定条件所需的重试操作，CD2401 DMA控制器不应编程为访问VMEbus。
DS200CTBAG1ADD通用模块硬件没有将CD2401限制为板载DRAM。
打印机接口MVME197LE具有与Centronics兼容的打印机接口。打印机接口由PCCCip2提供。请参阅MVME197LE、MVME197DP和MVME197SP单板计算机详细编程信息和打印机端口接口连接的图纸。以太网接口82596CA用于实现以太网收发器接口。这个82596CA使用DMA操作访问本地RAM以执行其正常操作功能。因为82596CA具有较小的内部缓冲区和VMEbus
如果DMA具有未定义的延迟期，则可能会发生缓冲区溢出编程为访问VMEbus。因此，82596CA不应编程为访问VMEbus。每个MVME197LE模块都分配了一个以太网站地址。这地址是$08003E2XXXXX，其中XXXXX是唯一的5位数字分配给板的以太网站地址显示在连接到VMEbus的标签上P2接头。此外，包括以太网地址在内的八个字节是存储在BBRAM的配置区域中，具有以下两个字节：这些设置为0。也就是说，08003E2xxxx00000存储在BBRAM中。在地址为$FFFC1F2C，可以读取上面的四个字节（08003E2X）。在地址为$FFFC1F30，可以读取较低的四个字节（XXXX0000）。提到本章后面将介绍BBRAM、TOD时钟内存映射。这个MVME197LE调试器能够检索或设置以太网
The interface provided by the PCCchip2 allows the 16-bit CD2401 to appear at
contiguous 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 boardThe 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
the BBRAM, TOD Clock memory map description later in this chapter. The
MVME197LE debugger has the capability to retrieve or set the Ethernet
