TWR-K60N512 and TWR-LCD RD pin connection

[rabbit]

In the "TWRLCDSCH.pdf", the RD pin (connector J2-pin33) is connected 3V3 via R18 resistor. I believe this will stop the K60 MCU reading the LCD.

the WR pin (connector J2-pin34) is connected to K60 MCU  FB_WR, the MCU can write to the LCD.

My question is if I want to read and write the LCD,  the LCD RD pin (connector J2-pin33)  should connect to which pin of K60 MCU?

Regards

Sam

[LuisCasado]

Hi Sam,

With the TWR-K60 and TWR-LCD hardware you can actually write and read the LCD data. You don't need any modification in hardware to read the TWR-LCD content using FlexBus.

Best Regards,

Luis

[friederschrempf]

Luis Casado schrieb:

With the TWR-K60 and TWR-LCD hardware you can actually write and read the LCD data. You don't need any modification in hardware to read the TWR-LCD content using FlexBus.

Is this also true for TWR-K70?

I tried to read the LCD content with the eGUI (D4D) function for FlexBus and MQX:

static unsigned short D4DLCDHW_ReadDataWord_Mqx(void)
{      
   return *((unsigned short*)BSP_EXTERNAL_LCD_BASE);
}

But this always returns zero, no matter what I have on the screen.

[LuisCasado]

Hello,

Check the wait states in the CS configuration for reading. The eGUI doesn't modify them, as eGUi is not reading the display at all.

Luis

[friederschrempf]

Thank you Luis for the hint! You led me on the right track!

With the help of AN4393, page 16 bottom I was able to modify the FlexBus configuration to read from TWR-LCD.

The FB_CLK is set to 40MHz in MQX, therefore I have 25ns for each cycle and at least 4 cycles are needed for each write/read cycle. According to the SSD1289 datasheet a write cycle needs at least 100ns, which is fine without wait state.

But the read cycle needs 1000ns. Therefore I added (1000ns - 4*25ns) / 25ns = 36 wait states.

In init_hw.c i modified the function _bsp_flexbus_lcd_setup:

fb_ptr->CS[0].CSCR =     FB_CSCR_BLS_MASK |
                                             FB_CSCR_AA_MASK  |
                                             FB_CSCR_WS(36)   |
                                             FB_CSCR_PS(2)    |
                                             FB_CSCR_BEM_MASK;

There also is an error in eGUI (v3 beta) read FlexBus MQX function:

static unsigned short D4DLCDHW_ReadDataWord_Mqx(void)
{       
   return *((unsigned short*)BSP_EXTERNAL_LCD_BASE;
}

should be:

static unsigned short D4DLCDHW_ReadDataWord_Mqx(void)
{       
   return *((unsigned short*)BSP_EXTERNAL_LCD_DC);
}

With these changes reading works fine and I can use the eGUI function D4D_PrintScreenToBMP to take screenshots from the LCD and write them to the attached USB device.

[apanecatl]

Hi Sam, you refer to "read" the information being displayed in the screen or reading the touch screen data through the 4 wire interface?