mac-rom-simm-programmer/tests/simm_electrical_test.c

263 lines
6.4 KiB
C

/*
* simm_electrical_test.c
*
* Created on: Nov 26, 2011
* Author: Doug
*/
#include "simm_electrical_test.h"
#include "../ports.h"
#include "../delay.h"
#define SIMM_HIGHEST_ADDRESS_LINE 20
#define SIMM_ADDRESS_PINS_MASK ((1UL << (SIMM_HIGHEST_ADDRESS_LINE + 1)) - 1)
#define SIMM_HIGHEST_DATA_LINE 31
#define SIMM_DATA_PINS_MASK (0xFFFFFFFFUL)
#define DELAY_SETTLE_TIME_MS 20
typedef enum ElectricalTestStage
{
TestingAddressLines,
TestingDataLines,
TestingCS,
TestingOE,
TestingWE,
DoneTesting
} ElectricalTestStage;
int SIMMElectricalTest_Run(void)
{
// Returns number of errors found
int numErrors = 0;
Ports_Init();
DelayMS(DELAY_SETTLE_TIME_MS);
// First check for anything shorted to ground. Set all lines as inputs with a weak pull-up resistor.
// Then read the values back and check for any zeros. This would indicate a short to ground.
Ports_SetAddressDDR(0);
Ports_SetDataDDR(0);
Ports_SetCSDDR(false);
Ports_SetOEDDR(false);
Ports_SetWEDDR(false);
Ports_AddressPullups_RMW(SIMM_ADDRESS_PINS_MASK, SIMM_ADDRESS_PINS_MASK);
Ports_DataPullups_RMW(SIMM_DATA_PINS_MASK, SIMM_DATA_PINS_MASK);
Ports_SetCSPullup(true);
Ports_SetOEPullup(true);
Ports_SetWEPullup(true);
DelayMS(DELAY_SETTLE_TIME_MS);
if (Ports_ReadAddress() != SIMM_ADDRESS_PINS_MASK)
{
// TODO: Log all these errors somewhere?
numErrors++;
}
if (Ports_ReadData() != SIMM_DATA_PINS_MASK)
{
// TODO: Log all these errors somewhere?
numErrors++;
}
if (!Ports_ReadCS())
{
// TODO: Log all these errors somewhere?
numErrors++;
}
if (!Ports_ReadOE())
{
// TODO: Log all these errors somewhere?
numErrors++;
}
if (!Ports_ReadWE())
{
// TODO: Log all these errors somewhere?
numErrors++;
}
// Now, check each individual line vs. all other lines on the SIMM for any shorts between them
ElectricalTestStage curStage = TestingAddressLines;
int x = 0;
while (curStage != DoneTesting)
{
// Set one pin to output a 0.
// Set all other pins as inputs with pull-ups.
// Then read back all the other pins. If any of them read back as 0,
// it means they are shorted to the pin we set as an output.
if (curStage == TestingAddressLines)
{
uint32_t addressLineMask = (1UL << x); // mask of the address pin we're testing
Ports_SetAddressDDR(addressLineMask); // set it as an output and all other address pins as inputs
Ports_AddressOut_RMW(0, addressLineMask); // set the output pin to output "0" without affecting the input pins
Ports_AddressPullups_RMW(~addressLineMask, SIMM_ADDRESS_PINS_MASK); // turn on the pullups on all input pins
}
else
{
// If not testing an address line, set all address pins as inputs with pullups.
// All the other stages follow the same pattern so I won't bother commenting them.
Ports_SetAddressDDR(0);
Ports_AddressPullups_RMW(SIMM_ADDRESS_PINS_MASK, SIMM_ADDRESS_PINS_MASK);
}
if (curStage == TestingDataLines)
{
uint32_t dataLineMask = (1UL << x);
Ports_SetDataDDR(dataLineMask);
Ports_DataOut_RMW(0, dataLineMask);
Ports_DataPullups_RMW(~dataLineMask, SIMM_DATA_PINS_MASK);
}
else
{
Ports_SetDataDDR(0);
Ports_DataPullups_RMW(SIMM_DATA_PINS_MASK, SIMM_DATA_PINS_MASK);
}
if (curStage == TestingCS)
{
Ports_SetCSDDR(true);
Ports_SetCSOut(false);
}
else
{
Ports_SetCSDDR(false);
Ports_SetCSPullup(true);
}
if (curStage == TestingOE)
{
Ports_SetOEDDR(true);
Ports_SetOEOut(false);
}
else
{
Ports_SetOEDDR(false);
Ports_SetOEPullup(true);
}
if (curStage == TestingWE)
{
Ports_SetWEDDR(true);
Ports_SetWEOut(false);
}
else
{
Ports_SetWEDDR(false);
Ports_SetWEPullup(true);
}
// OK, so now we have set up all lines as needed. Exactly one pin is outputting a 0, and all other pins
// are inputs with pull-ups enabled. Read back all the lines, and if any pin reads back as 0,
// it means that pin is shorted to the pin we are testing (overpowering its pullup)
DelayMS(DELAY_SETTLE_TIME_MS);
uint32_t readback = Ports_ReadAddress();
if (curStage == TestingAddressLines)
{
// Insert a high bit so our test doesn't fail on the pin we were testing
readback |= (1UL << x);
}
// At this point, any errors will manifest as 0 bits. It's easier to test for errors by turning them
// into 1 bits, so invert the readback so shorted pins are 1s and non-shorted pins are 0s
readback = ~readback & SIMM_ADDRESS_PINS_MASK;
// Count any shorted pins
while (readback)
{
numErrors++;
// The line below turns off the rightmost bit
// TODO: This will be useless unless I determine WHICH pin it is.
// But this makes a good placeholder for now.
readback = readback & (readback - 1);
}
readback = Ports_ReadData();
if (curStage == TestingDataLines)
{
// Insert a high bit so our test doesn't fail on the pin we were testing
readback |= (1UL << x);
}
// Again, invert readback so shorted pins are 1s and non-shorted pins are 0s
readback = ~readback;
// Count any shorted pins
while (readback)
{
numErrors++;
// The line below turns off the rightmost bit
// TODO: This will be useless unless I determine WHICH pin it is.
// But this makes a good placeholder for now.
readback = readback & (readback - 1);
}
if (curStage != TestingCS)
{
if (!Ports_ReadCS())
{
numErrors++;
// TODO: Report this error
}
}
if (curStage != TestingOE)
{
if (!Ports_ReadOE())
{
numErrors++;
// TODO: Report this error
}
}
if (curStage != TestingWE)
{
if (!Ports_ReadWE())
{
numErrors++;
// TODO: Report this error
}
}
// Finally, move on to the next stage if needed.
if (curStage == TestingAddressLines)
{
// If we've exhausted all address lines, move on to the next stage
// (and reset the pin counter to 0)
if (++x > SIMM_HIGHEST_ADDRESS_LINE)
{
curStage++;
x = 0;
}
}
else if (curStage == TestingDataLines)
{
// If we've exhausted all data lines, move on to the next stage
// (don't bother resetting the pin counter -- the other stages don't use it)
if (++x > SIMM_HIGHEST_DATA_LINE)
{
curStage++;
}
}
else
{
curStage++;
}
}
return numErrors;
}