| 摘要 |
A display unit includes a central processing unit (CPU) for outputting display data, a frame buffer having first and second ports and temporarily storing the display data received from the CPU via the first port, a display device having a display screen for displaying the display data read from the frame buffer means and received via the second port and having a display controller for generating and outputting image generating signals, a first control register for storing the display data output from the CPU and having a specific address, a second control register for reading the display data from the frame buffer and storing the display data in response to a register set signal, where the second control register supplies the display data stored therein to the CPU, and a comparator circuit for comparing the image generating signals output from the display controller and the display data stored in the first control register and for supplying the register set signal to the second control register when the image generating signals output from the display controller corresponds to the display data stored in the first control register. The CPU has a mechanism for comparing and checking the display data stored in the first control register and the display data stored in the second control register.
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