DS200SDCCG1AFD燃机模块,GE使用方法
VMEchip2中提供了看门狗定时器功能。当看门狗计时器已启用，必须在编程时间内通过软件重置，或它超时了。看门狗可以编程生成系统复位*信号、本地重置信号或板故障（如果超时）。参考VMEchip2MVME197LE、MVME197DP和MVME197SP单板中的章节计算机程序员详细编程参考指南信息软件可编程硬件中断8个软件可编程硬件中断由VMEchip2。这些中断允许软件创建硬件中断。请参阅MVME197LE、MVME197DP和MVME197SP单板计算机程序员参考指南编程信息。
DS200SDCCG1AFD燃机模块处理器总线超时总线开关为处理器总线提供总线超时电路。什么时候通过总线开关中的BTIMER寄存器启用，计时器开始计数
当DBB*被断言时，如果循环未终止（TA*、TEA*、或TRTRY*断言）在编程的超时时间之前，TEA*被断言。如果访问到本地外围总线，则禁用该计时器。
本地外围总线超时MVME197LE为处理器总线（MC88110）提供超时功能总线）和本地外围总线（MC68040兼容总线）。当计时器启用，总线访问超时，传输错误确认（TEA）信号生成。对于本地外围总线，软件可以选择8微秒、64微秒、256微秒或无限长的超时值。当地外围总线计时器在VMEbus绑定周期内不工作。VME总线绑定周期由VMEbus访问计时器和VMEbus全局计时器计时计时器。中断源MVME197LE微处理器中断通过总线开关传输。他们可能来自内部总线开关源以及PCCCip2（IPL总线开关的输入）、VMEchip2（总线开关的XIPL输入）和
其他外部来源（PALINT和IRQ）。总线开关也可能产生从中止按钮开关发送到微处理器的不可屏蔽中断（NMI）信号。请参阅中的总线开关、PCCCIP2和VMEchip2章节MVME197LE、MVME197DP和MVME197SP单板计算机程序员参考指南，了解更多详细信息。连接器
MVME197LE有两个64位DIN接头：P1和P2。连接器P1行A、B、C和连接器P2行B提供VMEbus互连。连接器P2第A行和第C行提供到SCSI总线的互连，即串行总线端口、以太网接口和Centronics打印机。有一个249针带有MC88110总线接口的夹层连接器（J2）。这个阁楼
连接器用于其他MVME197模块扩展。在MVME197LE上还有一个20针通用接头（J1），提供互连至LED以及复位和中止信号。此连接器是MVME197系列中的其他模块不同。参考电路板特定SIMVME197单板计算机支持信息手册详细的连接器信号描述。
Watchdog Timer
A watchdog timer function is provided in the VMEchip2. When the watchdog
timer is enabled, it must be reset by software within the programmed time or
it times out. The watchdog can be programmed to generate a SYSRESET*
signal, local reset signal, or board fail if it times out. Refer to the VMEchip2
chapter in the MVME197LE, MVME197DP, and MVME197SP Single Board
Computers Programmer’s Reference Guide for detailed programming
information.
Software-Programmable Hardware Interrupts
Eight software-programmable hardware interrupts are provided by the
VMEchip2. These interrupts allow software to create a hardware interrupt.
Refer to the VMEchip2 chapter in the MVME197LE, MVME197DP, and
MVME197SP Single Board Computers Programmer’s Reference Guide for detailed
programming information.
Processor Bus Timeout
The BusSwitch provides a bus timeout circuit for the processor bus. When
enabled by the BTIMER register in the BusSwitch, the timer starts counting
when DBB* is asserted, and if the cycle is not terminated (TA*, TEA*, or
TRTRY* asserted) before the programmed timeout period, TEA* is asserted.
This timer is disabled if the access goes to the local peripheral bus.
Local Peripheral Bus Timeout
The MVME197LE provides a timeout function for the processor bus (MC88110
bus) and for the local peripheral bus (MC68040 compatible bus). When the
timer is enabled and a bus access times out, a Transfer Error Acknowledge
(TEA) signal is generated. The timeout value is selectable by software for 8µsec, 64 µsec, 256 µsec, or infinite for the local peripheral bus. The local
peripheral bus timer does not operate during VMEbus bound cycles. VMEbus
bound cycles are timed by the VMEbus access timer and the VMEbus global
timer.
Interrupt Sources
MVME197LE MPU interrupts are channeled through the BusSwitch. They
may come from internal BusSwitch sources as well as from the PCCchip2 (IPL
inputs to the BusSwitch), the VMEchip2 (XIPL inputs to the BusSwitch), and
other external sources (PALINT and IRQ). The BusSwitch may also generate
