Patent ID: 7058732
Filing Date: 2006-06-06
Classification: G06F

Abstract:
1. A method of automatically detecting memory size comprising the steps of: a) sending a READ command from a memory controller chip to a serial peripheral interface (SPI) device over an SPI interface for a first series of eight serial clock cycles; b) driving a data Input/Output (D-IO) pin in said memory controller chip low for a second series of eight serial clock cycles; c) floating said D-IO pin after said second series of eight serial clock cycles, such that said D-IO pin is weakly pulled down in the absence of data from said SPI device and is overcome in the presence of data from said SPI device; d) automatically determining that said SPI device has memory addresses of up to nine bits when detecting the presence of a first non-zero value coming from said SPI device through said D-IO pin during a third series of eight serial clock cycles; and e) automatically determining that said SPI device has memory addresses of up to sixteen bits when detecting the presence of a first zero value at said D-IO pin during said third series of eight serial clock cycles and a second non-zero value coming from said SPI device through said D-IO pin during a fourth series of eight serial clock cycles.