DATA PROCESSOR

摘要

PURPOSE:To read out drive data with no use of an exclusive RAM by storing previously the drive data on an object to be driven in a prescribed address of a general-purpose RAM of a microcomputer and excluding this RAM out of the control of a CPU when the object to the driven is driven. CONSTITUTION:A ROM 20 is sued when the instruction of a general CPU 7 is decoded and gives a reading instruction to a general-purpose RAM 9 and at the same time separates the RAM 9 from the control of the CPU 7 after reception of a DMA request signal. A digit counter 13 counts clocks given from a display device clock generator 12 and these clocks are added to the RAM 9 via an address bus 18 for access. Thus the segment data stored in addresses A0-A3 of the RAM 9 are read out and held successively by a latch 14. Then the segment data is given to a segment driver 16 and applied to a display device 1.