Sourcecode/codec.c

Sample (pseudo) sourcecode to talk with the CODEC SPI interface.

Used for example to interface with the touchscreen.

static u32 cdcCurrentPage = 99;

u32 TouchReadBuffer(...)
{
	// Check if panel is touched (one of these 2):
	// val = CDC_ReadRegisterEx(3, 9)
	// val = CDC_ReadRegisterEx(3, 14)

	// if touched, read touch data into buf (2 bytes per touch position)
	// CDC_ReadRegistersEx(252, 1, buf, 20)
}

void CDC_ChangePage(u32 page)
{
	if (cdcCurrentPage == page)
		return;

	if (cdcCurrentPage == 0xFF)
		CDC_WriteRegister(0x7F, page);
	else
		CDC_WriteRegister(0, page);

	cdcCurrentPage = page;
}


void CDC_WriteRegister(u32 reg, u32 val)
{
	while(REG_SPICNT & 0x80);
	
	REG_SPICNT = 0x8A00;
	REG_SPIDATA = (reg<<1) & 0xFF;

	while(REG_SPICNT & 0x80);

	REG_SPICNT = 0x8200;
	REG_SPIDATA = val & 0xFF;
}

void CDC_WriteRegisterEx(u32 page, u32 reg, u32 val)
{
	CDC_ChangePage(page);
	CDC_WriteRegister(reg, val);
}

void CDC_WriteRegisters(u32 reg, u8* buf, u32 size)
{
	if (size == 0)
		return;


	while(REG_SPICNT & 0x80);

	REG_SPICNT = 0x8A00;
	REG_SPIDATA = (reg<<1) & 0xFF;

	while(REG_SPICNT & 0x80);

	while(size-- > 1)
	{
		REG_SPIDATA = 0;

		while(REG_SPICNT & 0x80);

		*buf++ = REG_SPIDATA;
	}

	REG_SPICNT = 0x8200;
	REG_SPIDATA = 0;

	while(REG_SPICNT & 0x80);

	*buf++ = REG_SPIDATA;
}

void CDC_WriteRegistersEx(u32 page, u32 reg, u8* buf, u32 size)
{
	CDC_ChangePage(page);
	CDC_WriteRegisters(reg, buf, size);
}

u32 CDC_ReadRegister(u32 reg)
{
	while(REG_SPICNT & 0x80);

	REG_SPICNT = 0x8A00;
	REG_SPIDATA = ((reg<<1) | 1) & 0xFF;

	while(REG_SPICNT & 0x80);

	REG_SPICNT = 0x8200;
	REG_SPIDATA = 0;

	while(REG_SPICNT & 0x80);

	return REG_SPIDATA;
}

u32 CDC_ReadRegisterEx(u32 page, u32 reg)
{
	CDC_ChangePage(page);
	return CDC_ReadRegister(reg);
}


void CDC_ReadRegisters(u32 reg, u8* buf, u32 size)
{
	if (size == 0)
		return;


	while(REG_SPICNT & 0x80);

	REG_SPICNT = 0x8A00;
	REG_SPIDATA = ((reg<<1)|1) & 0xFF;

	while(REG_SPICNT & 0x80);

	while(size-- > 1)
	{
		REG_SPIDATA = 0;

		while(REG_SPICNT & 0x80);

		*buf++ = REG_SPIDATA;
	}

	REG_SPICNT = 0x8200;
	REG_SPIDATA = 0;

	while(REG_SPICNT & 0x80);

	*buf++ = REG_SPIDATA;
}

void CDC_ReadRegistersEx(u32 page, u32 reg, u8* buf, u32 size)
{
	CDC_ChangePage(page);
	CDC_ReadRegisters(reg, buf, size);
}