RELIANCE 57C430B處理器模塊
這些特性使該裝置非常適合嵌入式應用，尤其是不能使用標準硬盤驅動器和軟盤驅動器的應用。概述VMIVME-7740提供了一個用戶可編程的82C54內(nèi)部計時器/計數(shù)器。82C54提供三個獨立的16位定時器，每個定時器的工作頻率為1或2MHz，由跳線E8的配置決定；參考第32頁表2-2。這些計時器對用戶完全可用，不專用于任何PC/AT功能。這些計時器可用于生成系統(tǒng)中斷。事件可以通過輪詢計時器或通過82C54外部電路生成系統(tǒng)中斷來計時。外部電路由產(chǎn)生中斷的邏輯和指示三個定時器中哪一個產(chǎn)生中斷的定時器中斷狀態(tài)寄存器組成。82C54定時器映射在I/O地址$500。計時器使用的中斷是IRQ5。定時器中斷狀態(tài)寄存器可通過電源管理I/O地址空間使用。對該空間的訪問在下面的“定時器中斷狀態(tài)”部分中進行了說明。
These features make the unit ideal for embedded applications, particularly applications where standard hard drives and floppy disk drives cannot be used.General The VMIVME-7740 provides a user-programmable 82C54 internal timer/counter. The 82C54 provides three independent, 16-bit timers, each operating at 1 or 2 MHz clock speed determined by the configuration of jumper E8; reference Table 2-2 on page 32. These timers are completely available to the user and are not dedicated to any PC/AT function. These timers may be used to generate system interrupts. Events can be timed by either polling the timers or generating a system interrupt via circuity external to the 82C54. The external circuity consists of logic which generates the interrupt and a Timer Interrupt Status register which indicates which of the three Timers generated an interrupt.The 82C54 timers are mapped at I/O address $500. The interrupt used by the Timers is IRQ5. The Timer Interrupt Status register is available via the Power Management I/O address space. The access to this space is explained in the “Timer Interrupt Status” section below.
