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allenhuffman
Joined: 17 Jun 2019
Posts: 639
Location: Des Moines, Iowa, USA
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| PIC24 PCD compiler and MPLAB X compiler I2C? |
 Posted: Thu Oct 02, 2025 4:01 pm |
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I have been trying to make common source files that work with our CCS PCD projects and a new one that is using the MPLAB X compiler.
I have been unable to find examples of this "Foundation Services Library" I2C code, and neither A.I. I have tried to use has produced code that fully works.
Original:
| Code: | bool AD5272WriteCommandData (unsigned int address, uint8_t command, uint16_t data)
{
bool status = false;
uint16_t value = (((uint16_t)command & AD5272_CMD_MASK) << 10) | (data & AD5272_DATA_MASK);
//AD5272_PRINTF ("AD5272WriteCommandData (0x%x, 0x%x, 0x%x)\r\n", address, command, data);
#if defined(__PCD__) // CCS PCD compiler.
unsigned int ackStatus = 0;
// Send start condition
i2c_start (AD5272_I2C_STREAM);
// Send address with write bit (0)
ackStatus = i2c_write (AD5272_I2C_STREAM, address << 1);
if (ackStatus == 0)
{
// ACK'd, so something is there, continue writing.
i2c_write (AD5272_I2C_STREAM, value >> 8);
i2c_write (AD5272_I2C_STREAM, value & 0xff);
status = true;
}
// Send stop condition
i2c_stop (AD5272_I2C_STREAM);
#else // assume MPLAB X compiler.
...snip...
#endif
return status;
} |
Does anyone here work with both systems?
The code that was presented to me in MPLABs uses "void i2c2_waitForEvent(uint16_t*);" over there, and looks like it may require some steps to have interrupts working.
I am using a PIC24FJ1024GA606 for this project, but I am happy with a polled I2C approach like we do in CCS. This MPLAB code looks like it wants interrupts, since that wait function is looking at slave and master IRQ bits.
_________________
Allen C. Huffman, Sub-Etha Software (est. 1990) http://www.subethasoftware.com
Embedded C, Arduino, MSP430, ESP8266/32, BASIC Stamp and PIC24 programmer.
http://www.whywouldyouwanttodothat.com ?
Using: 24FJ256GA106, 24EP256GP202 and 24FJ64GA002. |
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allenhuffman
Joined: 17 Jun 2019
Posts: 639
Location: Des Moines, Iowa, USA
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| Posted: Fri Oct 03, 2025 11:36 am |
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Wow, the "Foundation Services" functions in MPLAB are basically just C wrappers to I2C register calls. I've chatted with Bing Copilot, Google Gemini, and even Claude and none of them can produce working I2C code.
I have learned you need to manually clear IRQs (polled mode) and such, so I can at least see traffic and get responses from the chip, but it leaves the bus in a weird state according to the Saleae Logic captures I have done.
"The grass is always greener on the other side."
This is a good example of how easy the CCS routines are compared to what this MPLAB stuff seems to require -- and the MPLAB stuff is still not working the same way:
| Code: | uint16_t AD5272ReadCommandData (unsigned int address, uint8_t command, uint16_t data)
{
uint16_t retValue = 0;
uint16_t value = ((command & AD5272_CMD_MASK) << 10) | (data & AD5272_DATA_MASK);
//AD5272_PRINTF ("AD5272ReadCommandData (0x%x, 0x%x, 0x%x)\r\n", address, command, data);
#if defined(__PCD__) // CCS PCD compiler.
unsigned int ackStatus = 0;
// Send start condition
i2c_start (AD5272_I2C_STREAM);
// Send address with write bit (0)
ackStatus = i2c_write (AD5272_I2C_STREAM, address << 1);
if (ackStatus == 0)
{
// ACK'd, so something is there, continue writing.
uint8_t msb = 0;
uint8_t lsb = 0;
i2c_write (AD5272_I2C_STREAM, value >> 8); // MSB
i2c_write (AD5272_I2C_STREAM, value & 0xff); // LSB
// Send repeated start condition.
i2c_start (AD5272_I2C_STREAM);
// Send address with write bit (1)
i2c_write (AD5272_I2C_STREAM, (address << 1) | 1);
msb = i2c_read (AD5272_I2C_STREAM, 1); // ACK
lsb = i2c_read (AD5272_I2C_STREAM, 0); // No ACK
retValue = (msb << 8) | lsb;
}
// Send stop condition
i2c_stop (AD5272_I2C_STREAM);
#else // assume MPLAB X compiler.
// i2c2_driver_driver_open() is done during system startup.
unsigned int ackStatus = 0;
uint16_t event;
i2c2_driver_clearBusCollision ();
i2c2_driver_resetBus (); // Currently an empty function.
i2c2_clearIRQ (); // Clear the interrupt flag
// Send start condition
i2c2_driver_start ();
i2c2_waitForEvent (&event); // Wait for the event flag
i2c2_clearIRQ (); // Clear the interrupt flag
i2c2_driver_TXData (address << 1); // Address + Write
i2c2_waitForEvent (&event); // Wait for the event flag
i2c2_clearIRQ (); // Clear the interrupt flag
if (!i2c2_driver_isNACK())
{
ackStatus = true;
// ACK'd, so something is there, continue writing.
i2c2_driver_TXData (value >> 8); // MSB
i2c2_waitForEvent (&event); // Wait for the event flag
i2c2_clearIRQ (); // Clear the interrupt flag
i2c2_driver_TXData (value & 0xFF); // LSB
i2c2_waitForEvent (&event); // Wait for the event flag
i2c2_clearIRQ (); // Clear the interrupt flag
// Send repeated start condition.
i2c2_driver_restart ();
i2c2_waitForEvent (&event); // Wait for the event flag
i2c2_clearIRQ (); // Clear the interrupt flag
// Send address with write bit (1)
i2c2_driver_TXData ((address << 1) | 1);
i2c2_waitForEvent (&event); // Wait for the event flag
i2c2_clearIRQ (); // Clear the interrupt flag
}
// Only proceed to read if the initial write was ACK'd AND the Read address was ACK'd
if (ackStatus && !i2c2_driver_isNACK())
{
uint8_t msb = 0;
uint8_t lsb = 0;
// Prepare to receive
// BSET.B I2C2CON.RCEN ; Enable receive mode
i2c2_driver_startRX (); // RCEN=1
while (I2C2CONLbits.RCEN); // Wait for receive to complete
// BCLR.B I2C2CON.ACKDT ; ...send ACK
// BSET.B I2C2CON.ACKEN ; Send ACK/NACK
i2c2_driver_sendACK (); // ACKDT=0, ACKEN=1
// TODO: Wait for ACKDT/RCEN bits to clear?
while(I2C2CONLbits.ACKEN);
// BTSS.B I2C2STAT.RBF ; Wait for RBF (Receive Buffer Full)
while (!i2c2_driver_isBuferFull ());
// MOV I2C2RCV,W0 ; Read received byte into W0
msb = i2c2_driver_getRXData ();
// Clear overflow if needed.
if (I2C2STATbits.I2COV)
{
I2C2STATbits.I2COV = 0; // Clear overflow
}
i2c2_driver_startRX ();
while (I2C2CONLbits.RCEN); // Wait for receive to complete
i2c2_driver_sendNACK ();
while(I2C2CONLbits.ACKEN); // ACKDT=1, ACKEN=0
while (!i2c2_driver_isBuferFull ());
lsb = i2c2_driver_getRXData ();
if (I2C2STATbits.I2COV)
{
I2C2STATbits.I2COV = 0; // Clear overflow
}
retValue = (msb << 8) | lsb;
}
i2c2_driver_stop (); // STOP condition
i2c2_waitForEvent (&event); // Wait for the event flag
i2c2_clearIRQ (); // Clear the interrupt flag
// Ensure the bus is fully released by polling the PEN/TRSTAT bits.
while(I2C2CONLbits.PEN);
while(I2C2STATbits.TRSTAT);
#endif
return retValue;
} |
_________________
Allen C. Huffman, Sub-Etha Software (est. 1990) http://www.subethasoftware.com
Embedded C, Arduino, MSP430, ESP8266/32, BASIC Stamp and PIC24 programmer.
http://www.whywouldyouwanttodothat.com ?
Using: 24FJ256GA106, 24EP256GP202 and 24FJ64GA002. |
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