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AM335x processor LCD controller configuration

Tapas Maji
Prodigy 190 points
Other Parts Discussed in Thread: AM3354

Hi

In a custom board with AM3354BZCZA60, i'm using the following pins (LCD_DATA[15:0], LCD_PCLK, LCD_VSYNC, LCD_HSYNC and LCD_AC_BIAS_EN) of LCD controller as input or output, interfaced to an external device.

I do not want to use the LCD controller of AM3354, as there is no LCD required for the system. ( So both raster controller and LIDD controller have to be disabled.)

LCD_DATA[7:0]  as OUTPUT

LCD_DATA[11:8]  as IN/OUT

LCD_DATA[14:12]  as OUTPUT

LCD_DATA[15]  as INPUT.

LCD_PCLK as OUTPUT

LCD_VSYNC  as OUTPUT

LCD_HSYNC as INPUT

LCD_AC_BIAS_EN as INPUT

Then, what are the configurations to be made in order to use above LCD pins in user/general purpose IO mode?

a) PINMUX Configuration

b) Configuration registers setting

c) Is there a document which covers this mode of operation? (I could not find details on TRM spru73k.pdf)

Thanks and Regards

Tapas Maji

  • 0
    TI__Guru**** 393215 points

    Hi Tapas,

    Please refer to Table 4-1 in the AM335X Datasheet Rev. G for alternate functions of these pins. All of them can be set as GPIO. Pinmux is described in section 9.2.2 in the AM335X TRM Rev. K, and pad configuration registers are listed in Table 9-7 (conf_xxxxx registers).

    With LCD_DATA[15:0] pins you have to be extra careful, because they are also the SYSBOOT pins. Boot mode is selected by external pullup/pulldown  resistors tied to these pins. You must ensure that external devices connected to these pins do not override the chosen SYSBOOT state at reset release time.