/******************************************************************************
* Function Name: Swd_ReceiveByte
*******************************************************************************
*
* Summary:
* Receives a byte of data on the SWD lines (SWDIO, SWDCK)
*
* Parameters:
* None.
*
* Return:
* rxByte: Data byte received by host on SWDIO line (Least significant bit is
* first received bit)
*
* Note:
* This function is called for reading data bytes in a SWD Read Packet
*
******************************************************************************/
static u8 Swd_ReceiveByte(void)
{
u8 loop = 0;
u8 rxBit = 0;
u8 rxByte = 0;
/* Loop for 8-bits of a byte */
for(loop = 0; loop < 8; loop++)
{
SWDCK_OUTPUT_LOW;
/* Read the SWDIO input line */
rxBit = ReadSwdio();
SWDCK_OUTPUT_HIGH;
rxByte = rxByte >> 1;
if(rxBit) /* Received a '1' */
{
rxByte = rxByte | MSB_BIT_MASK;
}
else /* Received a '0' */
{
rxByte = rxByte & (~MSB_BIT_MASK);
}
}
return(rxByte);
}
/******************************************************************************
* 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_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);
}
