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Hello all,
I am using the MSP430FR5994 Launchpad and am unable to generate the CS (STE) using the DriverLib and EUSCI_B1 (SPI is in the primary module). I can produce the clock and MOSI signals, just not the STE. Below is a scope image, followed the SPI setup configuration snippet and finally followed by a simple loop in the next snippet.
Scope Image. Signals listed from top (yellow) to bottom (green) are SCLK, MOSI, MISO, #CS (notice it is always high)
I am using Mode 0 which samples data on the first transition of the clock. The interface for UCB1 are P5.0 (SIMO), P5.1 (SOMI), P5.2(SCLK) and P5.3I(STE).
uint8_t ArduCAM_SPI_Init() //init SPI interface
{
//Configure Pins for UCB1CLK P5.2
GPIO_setAsPeripheralModuleFunctionOutputPin(
GPIO_PORT_P5,
GPIO_PIN0 + GPIO_PIN2 + GPIO_PIN3,
GPIO_PRIMARY_MODULE_FUNCTION
);
//Configure Pins for UCB1TXD/UCB1SIMO, UCB1RXD/UCB0SOMI
GPIO_setAsPeripheralModuleFunctionInputPin(
GPIO_PORT_P5,
GPIO_PIN1,
GPIO_PRIMARY_MODULE_FUNCTION
);
PMM_unlockLPM5();
//Initialize SPI_B1 Master
EUSCI_B_SPI_initMasterParam SPI_B1_param = {0};
SPI_B1_param.selectClockSource = EUSCI_B_SPI_CLOCKSOURCE_SMCLK;
SPI_B1_param.clockSourceFrequency = ArduCAM_CLOCK_FREQ;
SPI_B1_param.desiredSpiClock = ArduCAM_DESIRED_SPI_FREQ;
SPI_B1_param.msbFirst = EUSCI_B_SPI_MSB_FIRST;
SPI_B1_param.clockPhase = EUSCI_B_SPI_PHASE_DATA_CAPTURED_ONFIRST_CHANGED_ON_NEXT;//EUSCI_B_SPI_PHASE_DATA_CHANGED_ONFIRST_CAPTURED_ON_NEXT;//
SPI_B1_param.clockPolarity = EUSCI_B_SPI_CLOCKPOLARITY_INACTIVITY_LOW;//EUSCI_B_SPI_CLOCKPOLARITY_INACTIVITY_HIGH;
SPI_B1_param.spiMode = EUSCI_B_SPI_4PIN_UCxSTE_ACTIVE_LOW; //EUSCI_B_SPI_3PIN;//
EUSCI_B_SPI_initMaster(EUSCI_B1_BASE, &SPI_B1_param);
//Enable SPI module
EUSCI_B_SPI_enable(EUSCI_B1_BASE);
//Clear RXIFG interrupt flag
EUSCI_B_SPI_clearInterrupt(EUSCI_B1_BASE, EUSCI_B_SPI_RECEIVE_INTERRUPT);
PMM_unlockLPM5();
// __enable_interrupt();
return 1;
}
The simple loop I am running (captured on the scope) is below. A couple of notes: I lifted most of the code from the OUT-OF-BOX example for my test. In that example, the CS was coded separately (it did not use the built in STE) and for some reason chose to use EUSCI_B_SPI_3PIN mode. My understanding is that 3PIN mode multiplexes SIMO/SOMI onto one physical wire. The SD card has separate SIMO and SOMI pins so why he did this I don't know. Anyone know? I am wondering if STE did not work in 3PIN mode which is why he coded his own..... if so isn't this an errata?
while(1)
{
uint16_t gie = __get_SR_register() & GIE; // Store current GIE state
while(!EUSCI_B_SPI_getInterruptStatus(EUSCI_B1_BASE, EUSCI_B_SPI_TRANSMIT_INTERRUPT));
EUSCI_B_SPI_transmitData(EUSCI_B1_BASE, 0x00 | 0x80); //register address 0
while(!EUSCI_B_SPI_getInterruptStatus(EUSCI_B1_BASE, EUSCI_B_SPI_TRANSMIT_INTERRUPT));
EUSCI_B_SPI_transmitData(EUSCI_B1_BASE, 0x55); //data 55
while(EUSCI_B_SPI_isBusy(EUSCI_B1_BASE));
// Dummy read to empty RX buffer and clear any overrun conditions
EUSCI_B_SPI_receiveData(EUSCI_B1_BASE);
__bis_SR_register(gie); // Restore original GIE state
}
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