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公开(公告)号：US4246637A
公开(公告)日：1981-01-20
申请号：US919107
申请日：1978-06-26
CPC分类号： G06F13/32
摘要： A data processor input/output controller which is particularly useful as a microcontroller for the transfer of data between a host processor and one or more peripheral input/output devices in a digital data processing system. This input/output (I/O) controller is a subchannel controller for offloading a goodly portion of the subchannel control function from the host processor. This I/O controller includes a microprocessor for assisting and supervising the controller internal operations. Also included in the controller is an automatic high-speed data bypass mechanism whereby data may be transferred from the host processor to the I/O device or vice versa without having to pass through the microprocessor and without requiring any intervention on the part of the microprocessor during such automatic transfer. Provision is made for enabling the microprocessor to perform other functions, such as the presentation of interrupts to the host processor and the servicing of additional I/O commands from the host processor concurrently with the transfer of data via the automatic bypass mechanism. This capability is particularly useful where two or more I/O devices are connected to the controller. The automatic bypass mechanism is constructed to communicate with the host processor in a cycle steal mode. A look-ahead mechanism is provided for more quickly issuing the cycle steal requests to the host processor when operating in the automatic bypass mode.
摘要翻译： 一种数据处理器输入/输出控制器，其特别用作用于在主处理器与数字数据处理系统中的一个或多个外围输入/输出设备之间传送数据的微控制器。 该输入/输出（I / O）控制器是用于从主处理器卸载子通道控制功能的很好部分的子通道控制器。 该I / O控制器包括用于辅助和监督控制器内部操作的微处理器。 还包括在控制器中的是一种自动高速数据旁路机制，其中数据可以从主机处理器传送到I / O设备，反之亦然，而不必通过微处理器而不需要微处理器的任何干预 在这种自动转移过程中。 提供了使微处理器能够执行其他功能，例如向主机处理器呈现中断，以及通过自动旁路机制与主机处理器同时传送数据的附加I / O命令的服务。 当两个或多个I / O设备连接到控制器时，此功能特别有用。 自动旁路机构被构造成以循环窃取模式与主机处理器进行通信。 提供了一种提前机制，用于在以自动旁路模式操作时更快地向主机处理器发出周期窃取请求。
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