/**
* @brief Test the first state transition
*
* When transitioning from UNKNOWN to a state, the TAP should be reset.
* If TRST is assigned, that signal should be used. Otherwise the TAP
* should be clocked 5 times with TMS high to enter into the RESET state.
*/
bool jtagTAP_TestTxFromUnknown()
{
//Setup
HasTRST = false;
TMSStateTx = 0;
TRSTChanged = 0;
InvalidSignal = false;
jtagTAP_Init();
//Test
jtagTAP_SetState(JTAGTAP_STATE_IDLE);
//Check
//Without TRST, TMS should be high for 5 clock cycles and then low for one.
//The earliest TMS value appears in the higher bits of TMSState so the ending
//value of TMS state should be 0x0000003E
ASSERT(TMSStateTx == 0x3E, "Incorrect transitions. TMS values are %08X, should be %08X", TMSStateTx, 0x3E);
ASSERT(TRSTChanged == 0, "TRST transitioned %i times. It shouldn't have", TRSTChanged);
//re-setup
HasTRST = true;
TMSStateTx = 0xFFFFFFFF;
TRSTChanged = 0;
jtagTAP_Init();
//Test
jtagTAP_SetState(JTAGTAP_STATE_IDLE);
//Check
//With TRST, TMS should be low for one clock cycle. TRST should toggle low then high.
//The ending value of TMS state should be 0xFFFFFFFE.
ASSERT(TMSStateTx == 0xFFFFFFFE, "Incorrect transitions. TMS values are %08X, should be %08X", TMSStateTx, 0xFFFFFFFE);
ASSERT(TRSTChanged == 2, "TRST transitioned %i times. It should have done it %i times", TRSTChanged, 2);
//Check that an invalid signal wasn't set at some point
ASSERT(!InvalidSignal, "An invalid signal was specified at some point");
return true;
}
/**
* @brief Test the RESET transitions
*
* When transitioning from a state to RESET, the TAP should walk the states
* and finish at reset. If TRST is assigned, that signal should be used and
* the state set as RESET with TMS high.
*/
bool jtagTAP_TestReset()
{
//Setup
HasTRST = false;
TMSStateTx = 0;
TRSTChanged = 0;
InvalidSignal = false;
TAPState = JTAGTAP_STATE_DR_SHIFT;
jtagTAP_SetState(JTAGTAP_STATE_RESET);
//Check
//Without TRST, TMS should be high for 5 clock cycles.
//The earliest TMS value appears in the higher bits of TMSState so the ending
//value of TMS state should be 0x0000001F
ASSERT(TMSStateTx == 0x1F, "Incorrect transitions. TMS values are %08X, should be %08X", TMSStateTx, 0x1F);
ASSERT(TRSTChanged == 0, "TRST transitioned %i times. It shouldn't have", TRSTChanged);
//re-setup
HasTRST = true;
TMSStateTx = 0x0FFFFFF0;
TRSTChanged = 0;
//Test
TAPState = JTAGTAP_STATE_DR_SHIFT;
jtagTAP_SetState(JTAGTAP_STATE_RESET);
//Check
//With TRST, TMS shouldn't change. TRST should toggle low then high.
//TMS should be set high and the state should be RESET
ASSERT(TMSStateTx == 0x0FFFFFF0, "Incorrect transitions. TMS values are %08X, should be %08X", TMSStateTx, 0x0FFFFFF0);
ASSERT(TRSTChanged == 2, "TRST transitioned %i times. It should have done it %i times", TRSTChanged, 2);
ASSERT(TAPState == JTAGTAP_STATE_RESET, "State isn't RESET: %i", TAPState);
ASSERT(TMSStateCurrent, "Current state of TMS isn't high");
//Check that an invalid signal wasn't set at some point
ASSERT(!InvalidSignal, "An invalid signal was specified at some point");
return true;
}
/**
* @brief Attempts to determine if a device is attached via JTAG
*
* For the provided pin combination, this function will reset the tap and scan
* out the data register, either getting an ID CODE, a BYPASS or garbage. It
* will attempt to analyse the results to see if it's a valid result.
*
* @param[in] tck The pin the TCK signal is on, for scanning
* @param[in] tms The pin the TMS signal is on, for scanning
*/
static void knock_ScanReset(unsigned int tck, unsigned int tms)
{
unsigned int count;
int unchanged_count = -1; //the first time through always results in a unchanged count
uint16_t data, data_changed = 0x0000;
uint16_t prev_data;
uint16_t data_interesting = 0x0000;
uint16_t scan_results[KNOCK_RESULTS];
jtagTAP_SetState(JTAGTAP_STATE_UNKNOWN);
jtagTAP_SetState(JTAGTAP_STATE_DR_SHIFT);
prev_data = GPIOD_IDR;
for(count = 0; count < KNOCK_RESULTS; ++count)
{
data = GPIOD_IDR;
data_changed = data ^ prev_data;
data_interesting |= data_changed;
prev_data = data;
scan_results[count] = data;
jtag_Clock();
if(data_changed == 0)
{
if(++unchanged_count == KNOCK_UNCHANGED)
{
break;
}
}
else
{
unchanged_count = 0; //something changed, reset the count.
}
}
if(data_interesting != 0)
{
//a line changed state at least once, lets inspect
unsigned int bit = 0;
for(bit = 0; bit < knock_PinCount; ++bit)
{
if(((data_interesting >> bit) & 0x01) == 1)
{
//this line changed
unsigned int index;
data_interesting &= ~(1 << bit); //mask off this bit, until it proves itself
for(index = 0; index < count; ++index)
{
if((((scan_results[index] >> bit) & 0x01) == 1) && (count - index >= 32))
{
//this could be a potential ID CODE, get it
uint32_t idcode = 0x80000000;
unsigned int code_end = index + 32;
while(++index < code_end)
{
idcode >>= 1;
idcode |= ((scan_results[index] >> bit) & 0x01) << 31;
}
if((idcode != 0xFFFFFFFF))
{
data_interesting |= (1 << bit); //this is interesting, keep it
}
--index; //fixup
}
}
}
}
knock_ScanResetFindTDI(tck, tms, data_interesting, scan_results[count-1], count);
}
