Memory Presence Detect
Original Publication Date: 1986-Aug-01
Included in the Prior Art Database: 2005-Mar-09
A method is provided for automatically detecting the extent of addressable memory available to a memory storage controller or microprocessor. A memory personalization feature at the silicon-chip level can be used to determine the amount of addressable memory available for system utilization instead of a dependence on card switches or initial program load (IPL) with a memory range check. Unused address pins at the module level are tied to VSS (ground) so that at system initialization time the controller or microprocessor can interrogate address pins to detect the presence of memory by supplying VDD through a current-limiting resistor to the address pins. When the detected logical value of an address pin is 0 (pin is at VSS), the controller or microprocessor determines the extent of memory at that level to be non-existent.