Display drive control circuit
View Patent ↗No flicker is displayed on the display screen during display of moving pictures and power consumption can be reduced by adding a high quality moving picture display function. Moreover, the number of times of transfer of moving pictures by comprising a still-picture·text·system·I/O bus·interface and a moving picture interface (external display interface), providing a display operation change register (DM) and a RAM access change register (RM) which are changed selectively depending on display content (display mode) displayed on a display device and displaying the display data on the display device via a picture memory even in the moving picture display mode.
1. A liquid crystal controller driver on a semiconductor chip, comprising:
first data terminals to which moving picture data is to be supplied;
a first terminal to which a vertical synchronization signal is to be supplied;
a second terminal to which a horizontal synchronization signal is to be supplied;
a third terminal to which a dotclock is to be supplied;
a fourth terminal to which an enable signal is to be supplied;
second data terminals to which still picture data is to be supplied;
a clock generation circuit for generating an internal operation clock signal;
an external display interface which is coupled to the first data terminals and the first to fourth terminals;
a system interface which is coupled to the second data terminals;
a memory which stores picture data to be displayed to a display panel to be coupled to the liquid crystal controller driver;
a display drive circuit which is coupled to the memory and which provides display data to the display panel in accordance with the picture data read from the memory;
a first register designating, at a time when reading the picture data from the memory, one of
a first read operation synchronized with the internal operation clock signal, and
a second read operation synchronized with the vertical synchronization signal, the horizontal synchronization signal and the dotclock; and
a second register designating, at a time when writing the picture data to the memory, one of
a first write operation in which the picture data provided to the system interface via the second data terminals is written to the memory, and
a second write operation in which the picture data provided to the external display interface via the first data terminals is written to the memory.
2. A liquid crystal controller driver according to claim 1 ,
wherein the enable signal has an active state and an non-active state, and
wherein the moving picture data supplied to the external display interface via the first data terminals is written into the memory in accordance with the active state of the enable signal.
3. A liquid crystal controller driver according to claim 1 , further comprising:
a third register for storing a start address and an end address of an area in the memory where the moving picture data is to be written.
4. A liquid crystal controller driver according to claim 1 ,
wherein the first and the second register are set by an instruction supplied to the system interface via the second data terminals.
5. A display driver on a semiconductor chip, comprising:
first data terminals coupled to receive moving picture data;
a first terminal coupled to receive a vertical synchronization signal;
a second terminal coupled to receive a horizontal synchronization signal;
a third terminal coupled to receive a dotclock;
a fourth terminal coupled to receive an enable signal;
second data terminals coupled to receive still picture data;
a clock generation circuit generating an internal clock signal;
a first interface circuit coupled to the first data terminals and to the first to fourth terminals;
a second interface circuit coupled to the second data terminals;
a memory which stores picture data to be displayed on a display panel;
a source driver which is coupled to an output of the memory and which provides to the display panel display data based on the picture data read from the memory;
a first register having:
a first state in which the memory is enabled to read in synchronization with the internal clock signal, and
a second state in which the memory is enabled to read in synchronization with the vertical synchronization signal, the horizontal synchronization signal and the dotclock; and
a second register having:
a first state in which the memory is enabled to write the still picture data provided to the second interface circuit via the second data terminals, and
a second state in which the memory is enabled to write the moving picture data provided to the first interface circuit via the first data terminals.
6. A display driver according to claim 5 ,
wherein the enable signal has an active state and an non-active state, and
wherein the moving picture data supplied to the first interface circuit via the first data terminals is written into the memory during the active state of the enable signal.
7. A display driver according to claim 5 , further comprising:
a third register for setting a start address and an end address of an area in the memory where the moving picture data is to be written.
8. A display driver according to claim 7 ,
wherein the first to third registers are set by an instruction supplied to the second interface circuit via the second data terminals.
9. A display driver according to claim 5 ,
wherein the first register further has a third state in which the memory is enabled to be read in synchronization with the internal clock signal and the vertical synchronization signal, and
wherein moving picture data provided to the second data terminals is written in the memory when the first register is in the third state.
10. A display driver according to claim 9 ,
wherein the enable signal has an active state and an non-active state, and
wherein the moving picture data supplied to the first interface circuit via the first data terminals is written into the memory during the active state of the enable signal.
11. A display driver according to claim 10 , further comprising:
a third register for storing both a start address and an end address of an area in the memory where the moving picture data is to be written.
12. A one chip display controller and driver for a liquid crystal display, comprising:
a first interface circuit with first data terminals coupled to receive moving picture data, a first terminal coupled to receive a vertical synchronization signal, a second terminal coupled to receive a horizontal synchronization signal, a third terminal coupled to receive a dotclock, and a fourth terminal coupled to receive an enable signal;
a second interface circuit with second data terminals coupled to receive still picture data;
a clock generation circuit generating an internal clock signal;
a memory which stores picture data to be displayed on a display panel;
a source driver which provides to the display panel display signals based on the picture data read from the memory;
a first register having:
a first state in which the memory is enabled to be read in synchronization with the internal clock signal, and
a second state in which the memory is enabled to be read in synchronization with the vertical synchronization signal, the horizontal synchronization signal and the dotclock; and
a second register having:
a first state in which the memory is enabled to write the still picture data provided to the second interface circuit via the second data terminals, and
a second state in which the memory is enabled to write the moving picture data provided to the first interface circuit via the first data terminals.
13. A one chip display controller and driver according to claim 12 ,
wherein the first register has a third state in which the memory is enabled to be read in synchronization with the internal clock signal and the vertical synchronization signal, and
wherein second moving picture data provided to the second data terminals are written in the memory when the first register is in the third state.
14. A one chip display controller and driver according to claim 13 ,
wherein the enable signal has an active state and an non-active state, and
wherein the moving picture data supplied to the first interface circuit via the first data terminals is written into the memory during the active state of the enable signal.
15. A one chip display controller and driver according to claim 14 , further comprising:
a third register for setting both a start address and an end address of an area in the memory where the moving picture data is to be written.
16. A one chip display controller and driver for a liquid crystal display, comprising:
a first interface circuit with first data terminals coupled to receive moving picture data, a first terminal coupled to receive a vertical synchronization signal, a second terminal coupled to receive a horizontal synchronization signal, a third terminal coupled to receive a dotclock, and a fourth terminal coupled to receive an enable signal;
a second interface circuit with second data terminals coupled to receive still picture data;
a clock generation circuit generating an internal clock signal;
a memory which stores picture data to be displayed on a display panel;
a source driver which provides to the display panel display signals based on the picture data read from the memory;
a first register capable of setting:
a first state in which the memory is enabled to be read in synchronization with the internal clock signal,
a second state in which the memory is enabled to be read in synchronization with the vertical synchronization signal, the horizontal synchronization signal and the dotclock; and
a second register capable of setting:
a first state in which the memory is enabled to write the still picture data provided to the second interface circuit via the second data terminals, and
a second state in which the memory is enabled to write the moving picture data provided to the first interface circuit via the first data terminals.
17. A one chip display controller and driver according to claim 16 ,
wherein the first register is further capable of setting a third state in which the memory is enabled to be read in synchronization with the internal clock signal and the vertical synchronization signal, and
wherein second moving picture data provided to the second data terminals are written in the memory when the first register is in the third state.
18. An one chip display controller and driver according to claim 16 ,
wherein the enable signal has an active state and an non-active state, and
wherein the moving picture data supplied to the first interface circuit via the first data terminals is written into the memory during the active state of the enable signal.
19. A one chip display controller and driver according to claim 16 , further comprising:
a third register for setting both a start address and an end address of an area in the memory where the moving picture data is to be written.
20. A one chip display controller and driver for a liquid crystal display, comprising:
a first interface circuit with first data terminals coupled to receive moving picture data, a first terminal coupled to receive a vertical synchronization signal, a second terminal coupled to receive a horizontal synchronization signal, a third terminal coupled to receive a dotclock, and a fourth terminal coupled to receive an enable signal;
a second interface circuit with second data terminals coupled to receive still picture data;
a clock generation circuit generating an internal clock signal;
a memory which stores picture data to be displayed on a display panel;
a source driver which provides to the display panel display signals based on the picture data read from the memory;
a first register capable of setting:
a first state in which the memory is enabled to be read in synchronization with the internal clock signal,
a second state in which the memory is enabled to read in synchronization with the vertical synchronization signal, the horizontal synchronization signal and the dotclock, and
a third state in which the memory is enabled to be read in synchronization with the internal clock signal and the vertical synchronization signal; and
a second register capable of setting:
a first state in which the memory is enabled to write the still picture data provided to the second interface circuit via the second data terminals, and
a second state in which the memory is enabled to write the moving picture data provided to the first interface circuit via the first data terminals.
21. A one chip display controller and driver according to claim 20 ,
wherein second moving picture data provided to the second data terminals are written in the memory when the first register is set to the third state.
22. A one chip display controller and driver according to claim 20 ,
wherein the enable signal has an active state and an non-active state, and
wherein the moving picture data supplied to the first interface circuit via the first data terminals is written into the memory during the active state of the enable signal.
23. A one chip display controller and driver according to claim 20 , further comprising:
a third register for setting both a start address and an end address of an area in the memory where the moving picture data is to be written.