SA811F主控板卡,ABB产品重量
❏ 不要短路。❏ 不要拆卸、变形或施加过大压力。
❏ 不要加热或焚烧。❏ 不要直接使用焊料。
❏ 不要使用不同型号的电池，也不要将新旧电池一起使用。❏ 不要充电。
❏ 始终检查正确的极性。可编程定时器在本地处理器可用的资源中，有许多可编程定时器。定时器并入PIB控制器，并Z8536 CIO设备如图1-1和图3-1所示。他们可编程为对处理器产生周期性中断。间隔计时器
SA811F主控板卡PCI-ISA网桥控制器有三个内置计数器，用作可编程间隔计时器。计数器分组为一个计时器PIB控制器中的定时器1装置。每个计数器输出都有一个特定的功能：❏ 计数器0与中断请求行IRQ0相关联。它可能是用于系统计时功能，例如时间功能。
❏ 计数器1为ISA内存生成刷新请求信号。这MVME2700中未使用计时器。
❏ 计数器2为上的扬声器输出功能提供音调PIB控制器（扬声器输出信号，可通过电缆连接至通过远程重置连接器连接外部扬声器）。间隔计时器使用OSC时钟输入作为其时钟源。这个
MVME2700使用14.31818 MHz时钟源驱动OSC引脚。
16位定时器MVME2700上有四个16位定时器。PIB控制器提供一个16位计时器；Z8536 CIO设备提供了另外三种。
有关对这些计时器进行编程的信息，请参阅Winbond W83C553 PIB控制器和Zilog Z8536 CIO设备。串行通信接口MVME2700使用Zilog Z85230 ESCC（增强串行通信控制器）来实现两个串行通信接口，通过P2路由。Z85230支持同步（SDLC/HDLC）和异步协议。这个MVME2700硬件支持110B/s的异步串行波特率至38.4Kb/s。
❏ Do not short circuit.
❏ Do not disassemble, deform, or apply excessive pressure.
❏ Do not heat or incinerate.
❏ Do not apply solder directly.
❏ Do not use different models, or new and old batteries together.
❏ Do not charge.
❏ Always check proper polarity.
Programmable Timers
Among the resources available to the local processor are a number of
programmable timers. Timers are incorporated into the PIB controller and
the Z8536 CIO device as diagrammed in Figure 1-1 and Figure 3-1. They
can be programmed to generate periodic interrupts to the processor.
Interval Timers
The PCI-ISA Bridge controller has three built-in counters that serve as
programmable interval timers. The counters are grouped into one timer
unit, Timer 1, in the PIB controller. Each counter output has a specific
function:❏ Counter 0 is associated with interrupt request line IRQ0. It can be
used for system timing functions, such as a timer interrupt for a
time-of-day function.
❏ Counter 1 generates a refresh request signal for ISA memory. This
timer is not used in the MVME2700.
❏ Counter 2 provides the tone for the speaker output function on the
PIB controller (the SPEAKER_OUT signal which can be cabled to an
external speaker via the remote reset connector).
The interval timers use the OSC clock input as their clock source. The
MVME2700 drives the OSC pin with a 14.31818 MHz clock source.
16-Bit Timers
Four 16-bit timers are available on the MVME2700. The PIB controller
supplies one 16-bit timer; the Z8536 CIO device provides the other three.
For information on programming these timers, refer to the data sheets for
the Winbond W83C553 PIB controller and the Zilog Z8536 CIO device.
Serial Communications Interface
The MVME2700 uses a Zilog Z85230 ESCC (Enhanced Serial
Communications Controller) to implement the two serial communications
interfaces, which are routed through P2. The Z85230 supports
synchronous (SDLC/HDLC) and asynchronous protocols. The
MVME2700 hardware supports asynchronous serial baud rates of 110B/s
to 38.4Kb/s.
