Display controller capable of accessing an external memory for gray scale modulation data

摘要

A display controller includes a data bus interface which transfers data to the display controller from external sources. A modulation data register coupled to the data bus interface receives a first quantity of modulation data through the data bus interface. A decoder coupled to the modulation data register receives the first quantity of modulation data and decodes graphics data according to the first quantity of modulation data in order to generate display data. A modulation data address counter counts quantities of modulation data that are transferred through the data bus interface and generates a load modulation data signal when a preprogrammed total quantity of modulation data has been transferred through the data bus interface. A method used by a display controller of accessing modulation data from an external memory is also disclosed.