System memory initialization with presence detect encoding.

摘要

The microcomputer architecture and method provide for automatic conveyance of system memory configuration information to a memory controller (112) which controls a system memory (110) having numerous allowable memory configurations. The system memory (110) is comprised of conventional SIMMs (1-N) which carry varying DRAM capacities. Each SIMM (1-N) bears a number of unused external pins, which can be used to decipher the DRAM configuration pertaining to that particular SIMM. The SIMMs (1-N) are arranged in pairs and only the unused pins of one SIMM per pair are monitored. During the initialization of the system memory (110), data signals from all of the recognized pins are transmitted to a programmable logic array (PAL) (116), which translates the data signals into a control signal encoding the entire system memory configuration. The control signal is transmitted to the memory controller (112), which recognizes the signals through internal software (227). The internal software (227) performs a two-step analysis to determine the system memory configuration and to insure that the configuration conforms to one of numerous preselected allowable configurations. <IMAGE>