HITEQUEST Apr 2001

Plug & Play

Alex P, National Semiconductor , Apr 2001
 
 
 

Introduction. Remember PC ISA cards (audio,modem, parallel and serial port controllers)? You used jumpers to set an I/O address space for each card to avoid conflicts on the bus. Manufacturers provided the information about these settings for each card. For the average user, this configuration process was unreliable and frustrating. The idea of PLug & Play is to optimally allocate system resources between cards and other devices without user intervention. In other words P&P is autoconfiguration. How it works. The major steps of auto configuration process are as follows: Put all cards in configuration mode. Isolate one P&P card at a time. Read card's resource requirements information (this information is written into onboard memory by manufacturer). Assign conflict free resources to each card. Activate all P&P cards and remove them from configuration mode. BIOS software performs the above operations. After operational system (Windows 95/98/00)is loaded, it gets P&P information from BIOS and loads device drivers. References: ISA system architecture .Tom Shanley,Don Anderson,1995 Plug and Play ISA specification. HITEQUEST Apr 2001