CCS/MSP430F5528: baudrate of SPI example.

Hyusim Park

Part Number: MSP430F5528

Tool/software: Code Composer Studio

UCA0CTL1 |= UCSWRST; // **Put state machine in reset**
UCA0CTL0 |= UCMST+UCSYNC+UCCKPL+UCMSB; // 3-pin, 8-bit SPI master
// Clock polarity high, MSB
UCA0CTL1 |= 0x40; // SMCLK
UCA0BR0 = 0x02; // /2
UCA0BR1 = 0; //
UCA0MCTL = 0; // No modulation
UCA0CTL1 &= ~UCSWRST; // **Initialize USCI state machine**
UCA0IE |= UCRXIE; // Enable USCI_A0 RX interrupt

How can I find out baudrate of SPI example?

I like to connect bluetoothmodule (SPTBLE-1S) with 1000000.

Will it work with this configuration???

over 8 years ago

0 Ryan Brown1 over 8 years ago

TI__Guru**** 223727 points

Your UCA0CTL1 setting should be 0x80 or 0xC0 to select SMCLK, 0x40 uses ACLK instead. Assuming that you have a default SMCLK of ~1 MHz then your baudrate is 1000000/2 = 500 kHz. The SPBTLE-1S SPI clock is low when inactive and data is valid on the trailing edge, therefore the UCCKPH and UCCKPL bits should be cleared. I'm not sure whether you should expect the MSB or LSB first, you will have to further consult the SPBTLE-1S resources.

Regards,
Ryan

0 Hyusim Park over 8 years ago in reply to Ryan Brown1

Prodigy 140 points

What do you mean that I have to clear the UCCKPH, UCCKPL can you explain more detail?
I am not familiar with the Microcontroller.

Thank you!

0 Ryan Brown1 over 8 years ago in reply to Hyusim Park

TI__Guru**** 223727 points

Well you never set UCCKPH in the first place but you likewise should not be setting UCCKPL in the UCA0CTL0 register.

Regards,
Ryan

**Attention** This is a public forum

MSP low-power microcontrollers

MSP low-power microcontroller forum

CCS/MSP430F5528: baudrate of SPI example.