/** Determines if a card has been inserted, and if so reads in each track's contents into the bit buffers
* until they are read out to the host as a series of keyboard presses.
*/
void ReadMagstripeData(void)
{
/* Arrays to hold the buffer pointers, clock and data bit masks for the separate card tracks */
const struct
{
uint8_t ClockMask;
uint8_t DataMask;
} TrackInfo[] = {{MAG_T1_CLOCK, MAG_T1_DATA},
{MAG_T2_CLOCK, MAG_T2_DATA},
{MAG_T3_CLOCK, MAG_T3_DATA}};
uint8_t Magstripe_Prev = 0;
uint8_t Magstripe_LCL = Magstripe_GetStatus();
while (Magstripe_LCL & MAG_CARDPRESENT)
{
for (uint8_t Track = 0; Track < TOTAL_TRACKS; Track++)
{
bool DataPinLevel = ((Magstripe_LCL & TrackInfo[Track].DataMask) != 0);
bool ClockPinLevel = ((Magstripe_LCL & TrackInfo[Track].ClockMask) != 0);
bool ClockLevelChanged = (((Magstripe_LCL ^ Magstripe_Prev) & TrackInfo[Track].ClockMask) != 0);
/* Sample data on rising clock edges from the card reader */
if (ClockPinLevel && ClockLevelChanged)
BitBuffer_StoreNextBit(&TrackDataBuffers[Track], DataPinLevel);
}
Magstripe_Prev = Magstripe_LCL;
Magstripe_LCL = Magstripe_GetStatus();
}
CurrentTrackBuffer = &TrackDataBuffers[0];
}
/** Main program entry point. This routine contains the overall program flow, including initial
* setup of all components and the main program loop.
*/
int main(void)
{
SetupHardware();
for (uint8_t Buffer = 0; Buffer < TOTAL_TRACKS; Buffer++)
BitBuffer_Init(&TrackDataBuffers[Buffer]);
for (;;)
{
if (Magstripe_GetStatus() & MAG_CARDPRESENT)
ReadMagstripeData();
HID_Device_USBTask(&Keyboard_HID_Interface);
USB_USBTask();
}
}