NHD-C0220BiZ-FSW-FBW-3V3M issues with TI MSP432P401R launchpad

Nzoka

• July 28, 2017 09:07

Hi,
First time using i2C.  As per page 4 of the Data sheet,
I have C = 1uF, 16V. 
R (The pullups) on SDA and SCL are 10kohms each.
I have a 1kohm pullup on RST and a 1kohm resistor from the Anode of the backlight to the 3.19V power supply.
I have a 0.1uF bypass capacitor across Vdd and Vss.

I am single stepping through my code and have a breakpoint set at 'line 1)' below

#define SLAVE_ADDRESS        0x78
....................................
 1)   MAP_I2C_masterSendSingleByte(EUSCI_B1_BASE, SLAVE_ADDRESS);
  2)  MAP_I2C_masterSendSingleByte(EUSCI_B1_BASE, 0x00);

When i step through at line 1, program does not exit to line 2
On halting, the code is hung up at last line in the module segment shown below.

void I2C_masterSendSingleByte(uint32_t moduleInstance, uint8_t txData)
{
    //Store current TXIE status
    uint16_t txieStatus = EUSCI_B_CMSIS(moduleInstance)->rIE.r & UCTXIE;

    //Disable transmit interrupt enable
    BITBAND_PERI(EUSCI_B_CMSIS(moduleInstance)->rIE.r,UCTXIE_OFS) = 0;

    //Send start condition.
    EUSCI_B_CMSIS(moduleInstance)->rCTLW0.r |= UCTR + UCTXSTT;

    //Poll for transmit interrupt flag.
    while (!(EUSCI_B_CMSIS(moduleInstance)->rIFG.r & UCTXIFG))
        ;

    //Send single byte data.
    EUSCI_B_CMSIS(moduleInstance)->rTXBUF.r = txData;

    //Poll for transmit interrupt flag.
    while (!(EUSCI_B_CMSIS(moduleInstance)->rIFG.r & UCTXIFG))
        ;

Attached is a screenshot when i execute line 1 (MAP_I2C_masterSendSingleByte(EUSCI_B1_BASE, SLAVE_ADDRESS)
Top plot is SCL
Bottom plot is SDA


These are voltage measurements
RST (Pin1)  3.187 V
VDD (Pin5) 3.188 V
VOUT (Pin6) 2.82 V
C1+ (Pin7) 3.17 V
C1- (Pin8) 0.015 V

A - 2.5 V
K - 0 V

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• 

  Saurabh_B

  • July 31, 2017 09:07

  Hello,
  
  Looking at your trace, it looks like you're clocking in the SDA on the falling edge.
  
  When you are sending the Address, it looks like you are sending a 0xF0 instead of the 78. Would you be able to try 0x3C for your address?

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• 

  Nzoka

  • July 31, 2017 10:07

  Thanks,
  I changed to 0x3C and can now perform the LCD initialization. And i have the cursor displayed.
  Help needed on how to switch to writing a character. Using the following code did not work.

  #define SLAVE_ADDRESS        0x3C 

  1)      MAP_I2C_masterSendMultiByteStart(EUSCI_B1_BASE, SLAVE_ADDRESS); // Start Transmission and send address 0x3C
  2)   MAP_I2C_masterSendMultiByteNext(EUSCI_B1_BASE, 0x40);  // data mode
  3)    MAP_I2C_masterSendMultiByteNext(EUSCI_B1_BASE, 0x46);   // Ascii 'D'
  4)    MAP_I2C_masterSendMultiByteStop(EUSCI_B1_BASE);  // End Transmission

  When i execute line 2, the cursor jumps to the start of the 2nd line.Next when i execute line 3, the cursor moves
  to 6 locations to the right.
  It looks like I still have 'RS=0'
  How can i change to having 'RS=1', so that data sent will go to the RAM and be subsequently displayed.
  
  Below is my LCD initialization code.  e.g my48Mdelayms(40) creates a delay of 40ms.

  my48Mdelayms(40);
      MAP_I2C_masterSendMultiByteStart(EUSCI_B1_BASE, SLAVE_ADDRESS); // Send Start followed by Start address
      MAP_I2C_masterSendMultiByteNext(EUSCI_B1_BASE, 0x00);
      MAP_I2C_masterSendMultiByteNext(EUSCI_B1_BASE, 0x38);  //Function set - 8 bit, 2 line display 5x8, inst table 0
      my48Mdelayms(10);
      MAP_I2C_masterSendMultiByteNext(EUSCI_B1_BASE, 0x39);   //Function set - 8 bit, 2 line display 5x8, inst table 1
      my48Mdelayms(10);
      MAP_I2C_masterSendMultiByteNext(EUSCI_B1_BASE, 0x14);  // Set bias - 1/5
      MAP_I2C_masterSendMultiByteNext(EUSCI_B1_BASE, 0x78);  // Set contrast low
      MAP_I2C_masterSendMultiByteNext(EUSCI_B1_BASE, 0x5E);  // ICON disp on, Contrast high byte
      MAP_I2C_masterSendMultiByteNext(EUSCI_B1_BASE, 0x6D);  // Follower circuit (internal), amp ratio (6)
      my48Mdelayms(300);
      MAP_I2C_masterSendMultiByteNext(EUSCI_B1_BASE, 0x0E);  // Display on, cursor on
      MAP_I2C_masterSendMultiByteNext(EUSCI_B1_BASE, 0x01);  // Clear display
      my48Mdelayms(2);
      MAP_I2C_masterSendMultiByteNext(EUSCI_B1_BASE, 0x06);  // Entry mode set - increment
      my48Mdelayms(2);
      MAP_I2C_masterSendMultiByteStop(EUSCI_B1_BASE);  // End Transmission

   

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• 

  Nzoka

  • August 01, 2017 10:07

  Thanks all,
  I have fixed the issue. I will post the code in another thread to help others in future.
  The main issue had to do with using the API:MAP_I2C_masterSendMultiByteStart(EUSCI_B1_BASE, xx)
  This API does the following:
  - Sends START
  - Sends 7-bit Device address
  - Sends byte xx.
  
  To enable command mode, i have to send:
  MAP_I2C_masterSendMultiByteStart(EUSCI_B1_BASE, 0x40);
  
  To enable data mode , i have to send:
  MAP_I2C_masterSendMultiByteStart(EUSCI_B1_BASE, 0x40);

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