/**
*
* This function changes the column, row position in the Instance structure
* of driver. It is used to correct the position for the next character to
* be written if column and row position cross limits.
*
* @param InstancePtr is a pointer to the XTft instance.
* @param ColVal is the column number to which ColVal member of
* Instance structure is updated. If ColVal crosses
* (XTFT_DISPLAY_WIDTH - 1) - XTFT_CHAR_WIDTH, position is
* moved to next line. The valid values are 0 to
* (XTFT_DISPLAY_WIDTH - 1).
* @param RowVal is the row number to which RowVal member of
* Instance structure is updated. If RowVal crosses
* (XTFT_DISPLAY_HEIGHT - 1)- XTFT_CHAR_HEIGHT, the first line
* will be deleted. The valid values are 0 to
* (XTFT_DISPLAY_HEIGHT - 1).
*
* @return None.
*
* @note This function differs from the function XTft_SetPos because
* you cannot move to any position on the screen as we have
* to check for enough space for a character to be written.
*
****************************************************************************/
void XTft_SetPosChar(XTft *InstancePtr, u32 ColVal, u32 RowVal)
{
/*
* Assert validates the input arguments.
*/
Xil_AssertVoid(InstancePtr != NULL);
Xil_AssertVoid(InstancePtr->IsReady == XIL_COMPONENT_IS_READY);
Xil_AssertVoid(ColVal <= (XTFT_DISPLAY_WIDTH - 1));
Xil_AssertVoid(RowVal <= (XTFT_DISPLAY_HEIGHT - 1));
/*
* If there is no space in the current line for the next char
* go to next line.
*/
if (ColVal > (XTFT_DISPLAY_WIDTH - 1) - XTFT_CHAR_WIDTH) {
ColVal = XTFT_DEF_COLVAL;
RowVal += XTFT_CHAR_HEIGHT;
}
/*
* If there is no space in the current line for the next char
* go to next line by deleting the first line.
*/
while (RowVal > (XTFT_DISPLAY_HEIGHT - 1) - XTFT_CHAR_HEIGHT) {
XTft_Scroll(InstancePtr);
RowVal -= XTFT_CHAR_HEIGHT;
}
/*
* Update the column, row position values.
*/
InstancePtr->ColVal = ColVal;
InstancePtr->RowVal = RowVal;
}
XStatus XTft_SetPos(XTft *InstancePtr, Xuint32 x, Xuint32 y)
{
XASSERT_NONVOID(InstancePtr != XNULL);
XASSERT_NONVOID(InstancePtr->IsReady == XCOMPONENT_IS_READY);
if (x > XTFT_DISPLAY_WIDTH - XTFT_CHAR_WIDTH)
{
x = 0;
y += XTFT_CHAR_HEIGHT;
}
while (y > XTFT_DISPLAY_HEIGHT - XTFT_CHAR_HEIGHT)
{
XTft_Scroll(InstancePtr);
y = y - XTFT_CHAR_HEIGHT;
}
InstancePtr->X = x;
InstancePtr->Y = y;
return XST_SUCCESS;
}
/**
*
* This is the example function which performs the following operations on
* the TFT device -
* - Set the color values of foreground and background
* - Write two characters (S) one after another
* - Write a string of characters
* - Draw a line and scroll the screen once
* - Disable the display (The screen goes blank)
* - Scroll the screen once and draw a line
* - Enable the TFT display
*
* @param TftDeviceId is the unique Id of the device.
*
* @return
* - XST_SUCCESS if successful.
* - XST_FAILURE if unsuccessful.
*
* @note None.
*
******************************************************************************/
int TftExample(u32 TftDeviceId)
{
int Status;
u8 VarChar;
XTft_Config *TftConfigPtr;
/*
* Get address of the XTft_Config structure for the given device id.
*/
TftConfigPtr = XTft_LookupConfig(TftDeviceId);
if (TftConfigPtr == (XTft_Config *)NULL) {
return XST_FAILURE;
}
/*
* Initialize all the TftInstance members and fills the screen with
* default background color.
*/
Status = XTft_CfgInitialize(&TftInstance, TftConfigPtr,
TftConfigPtr->BaseAddress);
if (Status != XST_SUCCESS) {
return XST_FAILURE;
}
/*
* Wait till Vsync(Video address latch) status bit is set before writing
* the frame address into the Address Register. This ensures that the
* current frame has been displayed and we can display a new frame of
* data. Checking the Vsync state ensures that there is no data flicker
* when displaying frames in real time though there is some delay due to
* polling.
*/
while (XTft_GetVsyncStatus(&TftInstance) !=
XTFT_IESR_VADDRLATCH_STATUS_MASK);
/*
* Change the Video Memory Base Address from default value to
* a valid Memory Address and clear the screen.
*/
XTft_SetFrameBaseAddr(&TftInstance, TFT_FRAME_ADDR);
XTft_ClearScreen(&TftInstance);
/*
* Initialize the variable VarChar to the value to be displayed on the
* screen.
* Set the foreground and background colors.
*/
VarChar = 'S';
XTft_SetColor(&TftInstance, FGCOLOR_VALUE, BGCOLOR_VALUE);
/*
* Write the character two times starting from top left corner
* (i.e. origin) of screen.
*/
XTft_Write(&TftInstance, VarChar);
XTft_Write(&TftInstance, VarChar);
/*
* Write a string which is displayed next to the two characters
* written previously.
*/
Status = TftWriteString(&TftInstance, (u8*)"TFT CONTROLLER\n");
if (Status != XST_SUCCESS) {
return XST_FAILURE;
}
/*
* Draw a line between the coordinates (X1,Y1) and (X2,Y2) which
* displays a vertical line in white color.
* Scroll the screen, so the two characters and string will be
* erased on screen.
*/
Status = TftDrawLine(&TftInstance, X1POS, Y1POS, X2POS, Y2POS,
WHITECOLOR_VALUE);
if (Status != XST_SUCCESS) {
return XST_FAILURE;
}
XTft_Scroll(&TftInstance);
/*
* Disable the display, the screen will be turned off.
*/
XTft_DisableDisplay(&TftInstance);
/*
* Even though the screen is turned off, we can still do operations on
* video memory.
* Scroll the screen.
* Draw a line between the coordinates (X1 + 10,Y1) and (X2,Y2) which
* is displayed at different position as X1 has some offset.
*/
XTft_Scroll(&TftInstance);
Status = TftDrawLine(&TftInstance, X1POS + 10, Y1POS, X2POS + 10,
Y2POS, WHITECOLOR_VALUE);
if (Status != XST_SUCCESS) {
return XST_FAILURE;
}
/*
* Enable the display. Screen will display two lines in white color.
* The first line from the left of screen is slightly above the
* second one indicating the scroll was successful.
*/
XTft_EnableDisplay(&TftInstance);
return XST_SUCCESS;
}