/******************************************************************************
* Function Name: Swd_SecondTurnAroundPhase
*******************************************************************************
*
* Summary:
* Generates one SWDCK clock cycle for Turnaround phase of a SWD packet.
* SWDIO drive mode is changed to CMOS output drive mode so that the host can
* write data on SWDIO.
*
* Parameters:
* None.
*
* Return:
* None.
*
* Note:
* This function is called during SWD Read/Write packets
*
******************************************************************************/
static void Swd_SecondTurnAroundPhase(void)
{
/* Change to CMOS output drive mode for host to write to SWDIO */
SetSwdioCmosOutput();
SetSwdckLow();
SetSwdckHigh();
}
/******************************************************************************
* Function Name: Swd_FirstTurnAroundPhase
*******************************************************************************
*
* Summary:
* Generates one SWDCK clock cycle for Turnaround phase of a SWD packet.
* SWDIO drive mode is changed to High-Z drive mode so that the host can read
* the data on the SWDIO.
*
* Parameters:
* None.
*
* Return:
* None.
*
* Note:
* This function is called during SWD Read/Write packets
*
******************************************************************************/
static void Swd_FirstTurnAroundPhase(void)
{
/* Change to High-Z drive mode for host to read the SWDIO line */
SetSwdioHizInput();
SetSwdckLow();
SetSwdckHigh();
}
/******************************************************************************
* Function Name: Swd_SendByte
*******************************************************************************
*
* Summary:
* Sends a byte of data on the SWD lines (SWDIO, SWDCK)
*
* Parameters:
* txByte: Data byte to be sent by host on SWDIO line (Least significant bit
* sent first)
*
* Return:
* None.
*
* Note:
* This function is called for sending SWD header data in SWD Read/Write
* packets, and also to send data in a SWD Write packet.
*
******************************************************************************/
static void Swd_SendByte(u8 txByte)
{
u8 loop = 0;
/* Loop for 8-bits of a byte */
for (loop = 0; loop < 8; loop++) {
if (txByte & LSB_BIT_MASK) { /* Send a '1' */
SetSwdckLow();
SetSwdioHigh();
SetSwdckHigh();
} else { /* Send a '0' */
SetSwdckLow();
SetSwdioLow();
SetSwdckHigh();
}
txByte = txByte >> 1; /* Make the next bit to send as LS bit */
}
}
/******************************************************************************
* Function Name: Swd_SendDummyClocks
*******************************************************************************
*
* Summary:
* Sends three SWDCK clock cycles with SWDIO line held low
*
* Parameters:
* None.
*
* Return:
* None.
*
* Note:
* This function is called during SWD Read/Write packets.
*
******************************************************************************/
static void Swd_SendDummyClocks(void)
{
u8 loop;
/* Send three SWDCK clock cycles with SWDIO line held low */
SetSwdioLow();
for (loop = 0; loop < NUMBER_OF_DUMMY_SWD_CLOCK_CYCLES; loop++) {
SetSwdckLow();
SetSwdckHigh();
}
}
/******************************************************************************
* Function Name: Swd_ReceiveParity
*******************************************************************************
*
* Summary:
* Receives the 1-bit parity data on SWD lines
*
* Parameters:
* None.
*
* Return:
* parity:
* 1-bit parity data returned as a byte (either '1' or '0')
*
* Note:
* This function is called during SWD Read packet
*
******************************************************************************/
static u8 Swd_ReceiveParity(void)
{
u8 parity;
/* Make the clock low, Read SWDIO data, Make Clock high */
SetSwdckLow();
parity = ReadSwdio();
SetSwdckHigh();
return(parity);
}
/******************************************************************************
* Function Name: Swd_SendParity
*******************************************************************************
*
* Summary:
* Sends the 1-bit parity data on SWD lines
*
* Parameters:
* parity:
* 1-bit parity data received as a byte (either '1' or '0')
*
* Return:
* None.
*
* Note:
* This function is called during SWD Write packet
*
******************************************************************************/
static void Swd_SendParity(u8 parity)
{
/* Make the clock low, Send SWDIO data, Make Clock high */
SetSwdckLow();
if (parity) {
SetSwdioHigh();
} else {
SetSwdioLow();
}
SetSwdckHigh();
}
/******************************************************************************
* Function Name: Swd_GetAckSegment
********************************************************************************
*
* Summary:
* Gets the 3-bit ACK response in a SWD packet
*
* Parameters:
* None.
*
* Return:
* ack:
* 3-bit ACK response is returned as a byte. Three possible return values are:
* 0x01 - SWD_OK_ACK
* 0x02 - SWD_WAIT_ACK
* 0x04 - SWD_FAULT_ACK
* Any other return value - Undefined ACK code.
* Treat it similar to SWD_FAULT_ACK and abort operation.
*
* Note:
* This function is called during SWD Read/Write packets
*
******************************************************************************/
static u8 Swd_GetAckSegment(void)
{
u8 ack = 0;
u8 receiveBit = 0;
u8 loop = 0;
/* ACK bits are received lsb bit first */
for (loop = 0; loop < NUMBER_OF_ACK_BITS; loop++) {
SetSwdckLow();
/* Store the ACK bit received */
receiveBit = ReadSwdio();
SetSwdckHigh();
/* Concatenate the ACK bit with ACK data byte */
ack = ack | (receiveBit << loop);
}
return (ack);
}
