Following some examples with the MSP430F5529 and using CCS, it is the turn to use the ADC12_A, which has a resolution of 12 bits, this time we will use the example called "MSP430F55xx_adc_01" included in the folder MSP430F552x Code Examples.
What does this example? Basically it configures to read the voltage through port A0 and attend it by means of an interruption (the system is in LowPowerMode until the interruption takes it out of there), when the voltage in A0 is greater than 0.5 * AVcc (considering that AVcc is connected to VCC, the value should be about 3.3V approximately, I have measured it with my multimeter and walked in the 3.5V) will turn on LED1, otherwise it will remain off.
Circuit:
Now reviewing the schematic of the experimental board, we will note that pin A0 is connected to DB0 (a Touch Pad) which will not serve to demonstrate this example, therefore I have decided to use the potentiometer that has the board, this is connected to A5 (as shown in the following image), to work properly we must activate P1.8 and leave jumper JP2.
Firmware:
Considering these modifications, the code is as follows::
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| /******************************************************************************* | |
| * | |
| * MSP-EXP430F5529_002: Ejemplo básico del ADC_12 | |
| * | |
| ******************************************************************************* | |
| * FileName: main.c | |
| * Processor: MSP430F5529 | |
| * Complier: CCS 7.2.0.00013 | |
| * Author: Pedro Sánchez Ramírez (MrChunckuee) | |
| * Blog: http://mrchunckuee.blogspot.com/ | |
| * Email: mrchunckuee.psr@gmail.com | |
| * Description: ADC12, Sample A5, Set P1.0 if A5 > 0.5*AVcc | |
| ******************************************************************************* | |
| * Rev. Date Comment | |
| * v0.01 30/08/2017 - Testing using MSP-EXP430f5529 USB Experimental Board | |
| * - Se usó el potenciómetro en A5, para ello se habilito | |
| * y se puso en alto a P8.0 | |
| ******************************************************************************/ | |
| #include <msp430.h> | |
| int main(void) | |
| { | |
| WDTCTL = WDTPW + WDTHOLD; // Stop WDT | |
| ADC12CTL0 = ADC12SHT02 + ADC12ON; // Sampling time, ADC12 on | |
| ADC12CTL1 = ADC12SHP; // Use sampling timer | |
| ADC12MCTL0 = ADC12INCH_5; // Use A5 (wheel) as input | |
| ADC12IE = 0x01; // Enable interrupt | |
| ADC12CTL0 |= ADC12ENC; // Enable conversions | |
| P6SEL |= BIT5; // P6.5 ADC option select (A5) | |
| P1DIR |= BIT0; // P1.0 output | |
| P8DIR |= BIT0; // P8.0 output | |
| P8OUT |= BIT0; // Set P8.0 high | |
| while (1) | |
| { | |
| ADC12CTL0 |= ADC12SC; // Start sampling/conversion | |
| __bis_SR_register(LPM0_bits + GIE); // LPM0, ADC12_ISR will force exit | |
| __no_operation(); // For debugger | |
| } | |
| } | |
| #pragma vector = ADC12_VECTOR | |
| __interrupt void ADC12_ISR(void) | |
| { | |
| switch(__even_in_range(ADC12IV,34)) | |
| { | |
| case 0: break; // Vector 0: No interrupt | |
| case 2: break; // Vector 2: ADC overflow | |
| case 4: break; // Vector 4: ADC timing overflow | |
| case 6: // Vector 6: ADC12IFG0 | |
| if (ADC12MEM0 >= 0x7ff) // ADC12MEM = A5 > 0.5AVcc? | |
| P1OUT |= BIT0; // P1.0 = 1 | |
| else | |
| P1OUT &= ~BIT0; // P1.0 = 0 | |
| __bic_SR_register_on_exit(LPM0_bits); // Exit active CPU | |
| case 8: break; // Vector 8: ADC12IFG1 | |
| case 10: break; // Vector 10: ADC12IFG2 | |
| case 12: break; // Vector 12: ADC12IFG3 | |
| case 14: break; // Vector 14: ADC12IFG4 | |
| case 16: break; // Vector 16: ADC12IFG5 | |
| case 18: break; // Vector 18: ADC12IFG6 | |
| case 20: break; // Vector 20: ADC12IFG7 | |
| case 22: break; // Vector 22: ADC12IFG8 | |
| case 24: break; // Vector 24: ADC12IFG9 | |
| case 26: break; // Vector 26: ADC12IFG10 | |
| case 28: break; // Vector 28: ADC12IFG11 | |
| case 30: break; // Vector 30: ADC12IFG12 | |
| case 32: break; // Vector 32: ADC12IFG13 | |
| case 34: break; // Vector 34: ADC12IFG14 | |
| default: break; | |
| } | |
| } |
Video
Here is a small working video:
Here is a small working video:
Download:
Here the direct link to DOWNLOAD the available files, you can also check or download the information from my repository on GitHub, if you do not know how to download it you can check here, well for now it's all, if you have doubts, comments, suggestions, concerns, etc. leave them and I will try to answer as soon as possible.
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- Texas Instruments, "MSP430F552x Code Examples", http://www.ti.com/lit/zip/slac300
- TI E2E Community, http://e2e.ti.com/
- Texas Intruments, "MSP430F5529 USB Experimenter’s Board", http://www.ti.com/tool/msp-exp430f5529
- Texas Instruments, 2016, "MSP430x5xx and MSP430x6xx Family", http://www.ti.com/lit/ug/slau208p/slau208p.pdf
- Texas Instrumetns, 2015, "MSP430F552x, MSP430F551x Mixed-Signal Microcontrollers", http://www.ti.com/lit/ds/symlink/msp430f5529.pdf
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