Two MAX7219 matrix LED program buggy

Now I am cascading two MAX7219 matrix LEDS.  I tried to display two characters, but only the first matrix displays the character.  I swapped the matrix LEDs then the original second, now first matrix LED display the character.  So it appears that the hardware connections are OK, the software has a bug.

From MAX7219 datasheet

...

No-Op Register

The no-op register is used when cascading MAX7219s or MAX7221s. 

Connect all devices’ LOAD/CS inputs together and connect DOUT to DIN on adjacent

devices. 

DOUT is a CMOS logic-level output that easily drives DIN of successively cascaded parts. (Refer to the Serial Addressing Modes section for detailed information on serial input/output timing.) 

For example, if four MAX7219s are cascaded, then to write to the fourth chip, sent the desired 16-bit word, followed by three no-op codes (hex 0xXX0X, see Table 2). When LOAD/CS goes high, data is latched in all devices. The first three chips receive no-op commands, and the fourth receives the intended data.

testMax7219SegmentLed01(SPI_CHANNEL_0);
testMax7219MatrixLed01(SPI_CHANNEL_1);

// ***************************************************************************

// Function - Test MAX7219 8x8 matrix LED

// Date     - 2013nov06

// ***************************************************************************

void testMax7219MatrixLed01(uint8_t spiChannelNumber)

{

setupSpi051(spiChannelNumber);

max7219MatrixLed01(spiChannelNumber);

}

// ***************************************************************************

// Function - Test MAX7219 7-segment LED

// Date     - 2013nov06

// ***************************************************************************

void testMax7219SegmentLed01(uint8_t spiChannelNumber)

{

setupSpi051(spiChannelNumber);

max7219SegmentLed01(spiChannelNumber);

}

// ***************************************************************************

// Function - Display 8x8 matrix LED

// Date     - 2013nov06

// ***************************************************************************

void max7219MatrixLed01(uint8_t spiChannelNumber)

{

    // *** Print project title ***********************************************

printf("\n\n*** Matrix LED 01 - 2013nov06hkt1154 ***\n\n");

// *** Setup MAX7219 digit control register buffer ***********************

#define BUFFER_SIZE 2

#define ADDRESS_INDEX 0

#define DATA_INDEX 1

uint8_t txBuffer[BUFFER_SIZE];

uint8_t rxBuffer[BUFFER_SIZE];

    // *** Setup SPI xferConfig ***

    SSP_DATA_SETUP_Type xferConfig;

    xferConfig.tx_data = txBuffer;

    xferConfig.rx_data = rxBuffer;

    xferConfig.length = BUFFER_SIZE;

    // *** Setup MAX7219 for digit decode and scan limit ***

    // setUpMax7219NoDecode(txBuffer, xferConfig, spiChannelNumber);

    // *** Setup Two MAX7219 ***

    setUpTwoMax7219NoDecode(txBuffer, xferConfig, spiChannelNumber);

    // *** Display 8 digits ***

    /*

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, DIGIT_ADDR_7, PATTERN_ALL_ON);

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, DIGIT_ADDR_6, PATTERN_ALL_ON);

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, DIGIT_ADDR_5, PATTERN_ALL_OFF);

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, DIGIT_ADDR_4, PATTERN_ALL_OFF);

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, DIGIT_ADDR_3, PATTERN_ALL_ON);

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, DIGIT_ADDR_2, PATTERN_ALL_OFF);

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, DIGIT_ADDR_1, PATTERN_ALL_ON);

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, DIGIT_ADDR_0, PATTERN_ALL_OFF);

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, OPERATION_ADDR, NORMAL);

    */

writeLedCommand(txBuffer, xferConfig, spiChannelNumber, SHUTDOWN_ADDR, SHUTDOWN_MODE);

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, DIGIT_ADDR_7, charA[0]);

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, DIGIT_ADDR_6, charA[1]);

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, DIGIT_ADDR_5, charA[2]);

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, DIGIT_ADDR_4, charA[3]);

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, DIGIT_ADDR_3, charA[4]);

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, DIGIT_ADDR_2, PATTERN_ALL_OFF);

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, DIGIT_ADDR_1, PATTERN_ALL_OFF);

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, DIGIT_ADDR_0, PATTERN_ALL_OFF);

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, DIGIT_ADDR_7, charA[0]);

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, DIGIT_ADDR_6, charA[1]);

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, DIGIT_ADDR_5, charA[2]);

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, DIGIT_ADDR_4, charA[3]);

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, DIGIT_ADDR_3, charA[4]);

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, DIGIT_ADDR_2, PATTERN_ALL_OFF);

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, DIGIT_ADDR_1, PATTERN_ALL_OFF);

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, DIGIT_ADDR_0, PATTERN_ALL_OFF);

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, OPERATION_ADDR, NORMAL);

}

// ***************************************************************************

// Function - Display 4 digits of 7-segment LED

// Date     - 2013nov06

// ***************************************************************************

void max7219SegmentLed01(uint8_t spiChannelNumber)

{

    // *** Print project title ***********************************************

printf("\n\n*** Segment LED 01 - 2013nov06hkt1128 ***\n\n");

// *** Setup MAX7219 digit control register buffer ***********************

#define BUFFER_SIZE 2

#define ADDRESS_INDEX 0

#define DATA_INDEX 1

uint8_t txBuffer[BUFFER_SIZE];

uint8_t rxBuffer[BUFFER_SIZE];

    // *** Setup SPI xferConfig ***

    SSP_DATA_SETUP_Type xferConfig;

    xferConfig.tx_data = txBuffer;

    xferConfig.rx_data = rxBuffer;

    xferConfig.length = BUFFER_SIZE;

    // *** Setup MAX7219 for digit decode and scan limit ***

    setUpMax7219BcdCodeB(txBuffer, xferConfig, spiChannelNumber);

    // *** Display 8 digits ***

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, DIGIT_ADDR_7, CHAR_H);

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, DIGIT_ADDR_6, CHAR_E);

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, DIGIT_ADDR_5, CHAR_L);

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, DIGIT_ADDR_4, CHAR_P);

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, DIGIT_ADDR_3, CHAR_BLANK);

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, DIGIT_ADDR_2, CHAR_BLANK);

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, DIGIT_ADDR_1, DIGIT_0);

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, DIGIT_ADDR_0, DIGIT_1);

    displayOneDigit(txBuffer, xferConfig, spiChannelNumber, OPERATION_ADDR, NORMAL);

}

// ***************************************************************************

// Function - Write MAX7219 command

// Date     - 2013nov06

// ***************************************************************************

void writeLedCommand(uint8_t txBuffer[BUFFER_SIZE], SSP_DATA_SETUP_Type xferConfig, \

            uint8_t spiChannelNumber, \

            uint8_t commandRegisterAddress, uint8_t command)

{

txBuffer[ADDRESS_INDEX] = commandRegisterAddress;

txBuffer[DATA_INDEX] = command;

    SpiWriteRead050(xferConfig, spiChannelNumber);

}

// ***************************************************************************

// Function - Display 1 digit

// Date     - 2013nov06

// ***************************************************************************

void displayOneDigit(uint8_t txBuffer[BUFFER_SIZE], SSP_DATA_SETUP_Type xferConfig, \

            uint8_t spiChannelNumber, \

            uint8_t digitAddress, uint8_t digitData)

{

writeLedCommand(txBuffer, xferConfig, spiChannelNumber, digitAddress, digitData);

}

// ***************************************************************************

// Function - Set up MAX7219 for Code B of all 8 digits, scan 8 digits

// Date     - 2013nov06

// ***************************************************************************

void setUpMax7219BcdCodeB(uint8_t txBuffer[BUFFER_SIZE], SSP_DATA_SETUP_Type xferConfig, \

                  uint8_t spiChannelNumber)

{

writeLedCommand(txBuffer, xferConfig, spiChannelNumber, SHUTDOWN_ADDR, SHUTDOWN_MODE);

    delayTime(ONE_FIFTH_SECOND);

    writeLedCommand(txBuffer, xferConfig, spiChannelNumber, \

               DECODE_MODE_ADDR, CODE_B_ALL_DIGITS);

    writeLedCommand(txBuffer, xferConfig, spiChannelNumber, \

               SCAN_LIMIT_ADDR, DISPLAY_8_DIGITS);

}

// ***************************************************************************

// Function - Set up MAX7219 for no decode all 8 digits, scan 8 digits

// Date     - 2013nov06

// ***************************************************************************

void setUpMax7219NoDecode(uint8_t txBuffer[BUFFER_SIZE], SSP_DATA_SETUP_Type xferConfig, \

                  uint8_t spiChannelNumber)

{

writeLedCommand(txBuffer, xferConfig, spiChannelNumber, SHUTDOWN_ADDR, SHUTDOWN_MODE);

    delayTime(ONE_FIFTH_SECOND);

    writeLedCommand(txBuffer, xferConfig, spiChannelNumber, \

               DECODE_MODE_ADDR, NO_DECODE_ALL_DIGITS);

    writeLedCommand(txBuffer, xferConfig, spiChannelNumber, \

               SCAN_LIMIT_ADDR, DISPLAY_8_DIGITS);

}

void setUpTwoMax7219NoDecode(uint8_t txBuffer[BUFFER_SIZE], SSP_DATA_SETUP_Type xferConfig, \

                  uint8_t spiChannelNumber)

{

writeLedCommand(txBuffer, xferConfig, spiChannelNumber, SHUTDOWN_ADDR, SHUTDOWN_MODE);

    delayTime(ONE_FIFTH_SECOND);

writeLedCommand(txBuffer, xferConfig, spiChannelNumber, SHUTDOWN_ADDR, SHUTDOWN_MODE);

    delayTime(ONE_FIFTH_SECOND);

    writeLedCommand(txBuffer, xferConfig, spiChannelNumber, \

               DECODE_MODE_ADDR, NO_DECODE_ALL_DIGITS);

    writeLedCommand(txBuffer, xferConfig, spiChannelNumber, \

               DECODE_MODE_ADDR, NO_DECODE_ALL_DIGITS);

    writeLedCommand(txBuffer, xferConfig, spiChannelNumber, \

               SCAN_LIMIT_ADDR, DISPLAY_8_DIGITS);

    writeLedCommand(txBuffer, xferConfig, spiChannelNumber, \

               SCAN_LIMIT_ADDR, DISPLAY_8_DIGITS);

}

.END