LM8500

LM8300/LM8400/LM8500 Four Wire Resistive Touchscreen Controller with Brownout PRELIMINARY October 2002 LM8300/LM8400/LM8500 Four Wire Resistive Touchscreen Controller with Brownout General Description The LM8300/8400/8500 is a 4-wire resistive touch screen controller. The controller samples and drives the touch screen without the need of any external hardware. The built in 10-bit A/D provides a maximum of 500 coordinate pairs per second (cpps). The data sampled from the touch screen is sent out on the UART at a speed of 38400 bps. The controller has a power-saving mode which causes the controller to self-power down when no touch is detected on the touch screen for a specified amount of time. In the Devices included in this datasheet: Device LM8300 LM8400 LM8500 Operating Voltage 3, 5 V 3, 5 V 5V Brownout Voltage 2.7 to 2.9 V No Brownout 4.17V to 4.5V Operating Frequency 3.27 MHz 3.27 MHz 3.27, 10 MHz I/O Pins 18 18 18 Packages 44 LLP, 44 PLCC, 48 TSSOP 44 LLP, 44 PLCC, 48 TSSOP 44 LLP, 44 PLCC, 48 TSSOP Temperature 0˚C to +70˚C 0˚C to +70˚C 0˚C to +70˚C self-power down mode, the current drawn is typically less than 2 µA. The device resumes normal operation when a touch is detected on the touch screen or communication is detected on the UART. In addition to the self-power down mode, the controller can be disabled by pulling the SHUTDOWN pin low. The controller resumes normal operation when the SHUTDOWN pin is tristated or pulled high. The controller has an internal non-volat...