I don't think that is a simple task but it is definelty possible.
If you are developing using the Standalone application for this reference design as a starting point, there is no exising character drawing API that I am aware of. However, I can think of two ways that you could implement this support on your own. You could use a sprite map similar to what was done in the old PC gaming days and simply write image information to the display containing pixel data to form a letter. You can get pretty fancy with this method by using graphic design software to create the sprite map. Alternatively, you could write a library of routines to draw characters on the display by plotting pixels and then write some higher level functions to call the letter plot functions.
Take a look at this function from zed_hdmi_display.c where the colorbars are painted inside of the frambuffer space:
int zed_hdmi_display_cbars( zed_hdmi_display_t *pDemo, Xuint32 offset )
Xuint32 frame, row, col;
Xuint32 cbar, pixel;
volatile Xuint32 *pStorageMem = (Xuint32 *)pDemo->uBaseAddr_MEM_HdmiDisplay;
for ( frame = 0; frame < pDemo->uNumFrames_HdmiDisplay; frame++ )
for ( row = 0; row < pDemo->hdmio_height; row++ )
for ( col = 0; col < pDemo->hdmio_width; col++ )
cbar = (col * 8) / pDemo->hdmio_width; // color bar = 0..7
cbar = (cbar + offset) % 8;
switch ( cbar )
case 0: pixel = 0x00000000; break; // Black
case 1: pixel = 0x00FF0000; break; // Red
case 2: pixel = 0x0000FF00; break; // Green
case 3: pixel = 0x000000FF; break; // Blue
case 4: pixel = 0x0000FFFF; break; // Cyan
case 5: pixel = 0x00FF00FF; break; // Purple
case 6: pixel = 0x00FFFF00; break; // Yellow
case 7: pixel = 0x00FFFFFF; break; // White
*pStorageMem++ = pixel;
// Wait for DMA to synchronize.
You could do something similar but instead paint pixels to form letters. One thing I have done in the past is take a graphics image from Protoshop and convert to 24-bit RGB format then write that data into the framebuffer space. The image should then display on the HDMI display.
Thank you very much for your reply Kevin. I had thought to do something like that but excessively complicate the application I want to develop. I will try to use Petalinux or some variant of Linux to give me support with HDMI and other peripherals.