US 7,573,438 B2
Display device and portable electronic device
Koichi Nohara, Ome (Japan)
Assigned to Kabushiki Kaisha Toshiba, Tokyo (Japan)
Filed on Sep. 17, 2004, as Appl. No. 10/942,931.
Claims priority of application No. 2004-232514 (JP), filed on Aug. 09, 2004.
Prior Publication US 2006/0028395 A1, Feb. 09, 2006
Int. Cl. G09G 5/00 (2006.01)
U.S. Cl. 345—1.1 18 Claims
OG exemplary drawing
 
1. A display device comprising:
a first display;
a first display control circuit configured to control display operation in the first display;
a second display configured to be arranged independently of the first display;
a second display control circuit configured to control display operation in the second display;
a signal transmission path including shared signal lines connected to both the first display and the second display;
a switching circuit configured to connect the shared signal lines with the first display control circuit while disconnecting the shared signal lines from the second display control circuit, and alternately to connect the shared signal lines with the second display control circuit while disconnecting the shared signal lines from the first display control circuit, by the signal transmission path; and
a switching control circuit configured to perform switching control of the switching circuit in synchronism with display control by the first display control circuit and the second display control circuit,
wherein when the signal transmission path is switched from a first state in which the first display and the first display control circuit are connected to a second state in which the second display and the second display control circuit are connected, the first display control circuit, the second display control circuit, and the switching control circuit invalidate a chip select of the first display, stop transmission of display data to the first display, switch the signal transmission path from the first state to the second state by using the switching circuit, start supply of display data to the second display, and validate a chip select of the second display.