BU21028FV-M Datasheet, PDF (9/36 Pages) Rohm – 4-wire Resistive Touch Screen Controller

BU21028FV-M
CF= 0x0 (0000) : Automatic scan
This makes BU21028FV-M periodically and automatically scan the screen and convert data upon detecting touch. When
the device cannot detect touch, it stops and stays in power down state until it detects the next pen-down. The order of scan
process is Z1, Z2, X and Y.
CF= 0x1 (0001), 0x6 (0110), 0x7 (0111), 0xB (1011)
No operation. (“PDM” and “STP” is valid.)
CF = 0x2 (0010)
This converts the voltage impressed to AUX. After the conversion has been completed, the device is powered
down according to the PDM setting.
CF= 0x4 (0100) : Free scan mode
In Free Scan Mode, the driver state (X+, X-, Y+, Y-) and conversion input (X+, X-, Y+, Y-, AUX) can be selected through
register settings.
CF= 0x5 (0101) : Calibration
This calibrates the parameters for dual touch detection. To activate the dual touch function, setting of CF to 0101 and
execution of the calibration command should be done after power-on.
CF= 0x8 (1000), 0x9 (1001), 0xA (1010): Drivers status control
This activates the analog circuit and panel driver corresponding to each command. BU21028FV-M remains in this state until
it receives another SCAN instruction or until "STP" is set.
CF= 0xC (1100), 0xD (1101), 0xE (1110): Manual scan
This converts coordinates that correspond to each command. BU21028FV-M goes to power-down state after a complete
conversion if "PDM" is set to "0". Otherwise, it stays at power-on state.
CF =0x3 (0011), 0xF (1111)
Reserved.
Bit D2：CMSK
0=Executes convert function.
1=Reads the convert result
Bit D1：PDM
Power Down Control
0= Powers down the device after converter function stops
1= Keeps power on after converter function stops
Bit D0：STP
1= Aborts currently running conversion and changes the state to power-down (STP is automatically set to “0”.)
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TSZ02201-0L5L0F300720-1-2
27.May.2016 Rev.002