/**
*
* This function performs one of the following three operations based on the
* CharValue passed :
* - Move the position to the next line at the same position.
* - Move the position to the next line.
* - Write a particular character and update the column position by the
* width of the character.
*
* @param InstancePtr is a pointer to the XTft instance.
* @param CharValue is the ASCII code value of the character to be
* written.
*
* @return None.
*
* @note As the character bitmap array does not support some of the
* ASCII values, to support some of those which carry
* significance in display are added in the switch case. If
* there is a necessity for any other characters, it can be
* added here.
*
****************************************************************************/
void XTft_Write(XTft *InstancePtr, u8 CharValue)
{
/*
* Assert validates the input arguments.
*/
Xil_AssertVoid(InstancePtr != NULL);
Xil_AssertVoid(InstancePtr->IsReady == XIL_COMPONENT_IS_READY);
/*
* First two cases handle the special input values
* and default case performs a character write operation
* and it updates the column position in the instance structure.
*/
switch (CharValue) {
case 0xd:
/*
* Action to be taken for carriage return.
*/
XTft_SetPos(InstancePtr, XTFT_DEF_COLVAL,
InstancePtr->RowVal);
break;
case 0xa:
/*
* Action to be taken for line feed.
*/
XTft_SetPos(InstancePtr, XTFT_DEF_COLVAL,
InstancePtr->RowVal + XTFT_CHAR_HEIGHT);
break;
default:
/*
* Set the position and write the character and
* update the column position by width of
* character.
*/
XTft_SetPosChar(InstancePtr, InstancePtr->ColVal,
InstancePtr->RowVal);
XTft_WriteChar(
InstancePtr, CharValue,
InstancePtr->ColVal, InstancePtr->RowVal,
InstancePtr->FgColor, InstancePtr->BgColor);
InstancePtr->ColVal += XTFT_CHAR_WIDTH;
break;
}
}
int initTFT()
{
int Status;
XTft_Config *TftConfigPtr;
/*
* Get address of the XTft_Config structure for the given device id.
*/
TftConfigPtr = XTft_LookupConfig(TFT_DEVICE_ID);
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);
XTft_SetPos(&TftInstance, 0,0);
XTft_SetPosChar(&TftInstance, 0,0);
XTft_SetColor(&TftInstance, 0x00000000, 0x00ffffff);
XTft_FillScreen(&TftInstance, 0, 0,639,479,0x00ffffff); // white
return XST_SUCCESS;
}
XStatus XTft_Write(XTft *InstancePtr, Xint8 val)
{
XASSERT_NONVOID(InstancePtr != XNULL);
XASSERT_NONVOID(InstancePtr->IsReady == XCOMPONENT_IS_READY);
switch (val)
{
case 0xd: /* carriage return */
XTft_SetPos(InstancePtr, 0, InstancePtr->Y);
break;
case 0xa: /* line feed */
XTft_SetPos(InstancePtr, 0, InstancePtr->Y+XTFT_CHAR_HEIGHT);
break;
default:
XTft_SetPos(InstancePtr, InstancePtr->X, InstancePtr->Y);
XTft_WriteChar(*(Xuint32 *)InstancePtr->BaseAddress, val,
InstancePtr->X, InstancePtr->Y,
InstancePtr->FgColor, InstancePtr->BgColor);
InstancePtr->X += XTFT_CHAR_WIDTH;
break;
}
return XST_SUCCESS;
}