Cypress CY62158EV30 Manual do Utilizador descarregar pdf (Página 18)

18 September 5, 2010

 Wide temperature range

 White LED backlight

 Integrated RAM

 Resistive touch panel

Control Interface

The Color LCD module has a built-in controller IC with a multi-mode parallel interface. The

development board uses an 8-bit 8080 type interface with GPIO Port D providing the data bus.

Table 2-4 shows the LCD-related signals.

Backlight

The white LED backlight must be powered for the display to be clearly visible. U7 (FAN5331B)

implements a 20 mA constant-current LED power source to the backlight. The backlight is not

normally controlled by the microcontroller, however, the control signal is available on a header. A

jumper may be installed to disable the backlight by connecting it to GND. Alternatively, a wire may

be used to control this signal from a spare microcontroller GPIO line.

Because the FAN5331B operates in a constant current mode, its output voltage will jump up if the

LCD should become disconnected. To prevent over-voltage failure of the IC or diode D3, a zener

(D4) clamps the voltage. The current will limit to 20 mA, but the total board current will be higher

than when the LCD panel is connected. To avoid over-heating the backlighting circuit, install the

BLON jumper to completely shut-down the backlighting circuit.

Power

The LCD module has internal bias voltage generators and requires only a single 3.3 V dc supply.

Resistive Touch Panel

The 4-wire resistive touch panel interfaces directly to the microcontroller, using 2 ADC channels

and 2 GPIO signals. See the StellarisWare™ source code for additional information on touch panel

implementation.

Table 2-5. LCD-Related Signals

Microcontroller Pin Board Function Jumper Name

PE6/ADC1 Touch X+ X+

PE3 Touch Y- Y-

PE2 Touch X- X-

PE7/ADC0 Touch Y+ Y+

PB7 LCD Reset LRSTn

PD0..7 LCD Data Bus 0..7 LD0..7

PH7 LCD Data/Control Select LDC

PB5 LCD Read Strobe LRDn

PH6 LCD Write Strobe LWRn

- Backlight control BLON

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