| 摘要 |
PROBLEM TO BE SOLVED: To suppress data in a volatile memory from being lost during shifting to a mode for reducing power consumption.SOLUTION: A CPU 22 in an operation unit 3 side disables information communication with a controller 2 via USB signal lines L1, L3 after operating the self refresh function of a DDR memory 21 according to the instruction for shifting to a STR mode via the USB signal lines L1, L3. A CPU 11 in a controller 2 side stops power supply to the respective parts in the operation unit 3 excepting the DDR memory 21 by controlling an energy saving control circuit 25 via a control line L6 in a timing when the information communication with the operation unit 3 via the USB signal lines L1, L3 is disabled. |
