- We will be testing eMIOS by generating 6 PWM output simultaneously and will be changing its duty cycle in run time using Potentiometer which is connected to ADC0 input. At the same time, ADC input is indicated using 4 LEDs as follows:
Program Outcome:
20KHz PWM at eMIOS0_1 => PA[1], eMIOS0_2 => PA[2], eMIOS0_3 => PA[3], eMIOS0_4 => PA[4], eMIOS0_5 => PA[5], eMIOS0_6 => PA[6]. Initial Duty_Cycle = 10% Input(Analog) => Output PB[8] (ADC0_S0) => (eMIOS0_1 to eMIOS0_6) & [LED1 LED2 LED3 LED4] ADC0 = [0 to 1023] => Duty_Cycle = [0% to 98%] & LED Indication Input Pot value (Digital) => [LED1 LED2 LED3 LED4] Output 0 to 200 => ON OFF OFF OFF 201 to 500 => ON ON OFF OFF 501 to 800 => ON ON ON OFF 801 to 1023 => ON ON ON ON
Changelog:
26/03/2016: Bug:Phase lag of 1uSec is present between (eMIOS0_1,2,3) and (eMIOS0_4,5,6) 26/03/2016: Bug:Phase lag of 1uSec is present between (eMIOS0_1,2,3) and (eMIOS0_4,5,6) 01/04/2016: Phase lag removed. [clear the GTBE bit at beginning of Init_eMIOS() and set it at the end of the Init_eMIOS().] 18/04/2016: Remove PCTL[32] & PCTL[68] command from InitModesAndClks function to run eMIOS and ADC together
Connections:
eMIOS No. => Port No. => Pad No. => Pin No.(144-pin LQFP package) eMIOS0_1 => PA[1] => PCR[1] => PIN 11 eMIOS0_2 => PA[2] => PCR[2] => PIN 9 eMIOS0_3 => PA[3] => PCR[3] => PIN 90 eMIOS0_4 => PA[4] => PCR[4] => PIN 43 eMIOS0_5 => PA[5] => PCR[5] => PIN 118 eMIOS0_6 => PA[6] => PCR[6] => PIN 119 SIGNAL ADC0_Channel PORT SIU_PAD_CONFIG PACKAGE_PIN (100 144 176) ANS0 => 32 B8 PCR[24]=2000 39 53 R9 ANS1 => 33 B9 PCR[25]=2000 38 52 T9 ANS2 => 34 B10 PCR[26]=2000 40 54 P9 Potentiometer is connected to ANS0 (B8) for this program.
Calculations:
Frequency Calculation of PWM: For "x" Hz Frequency, B_VAL = 1/[(x)*10^-6] Duty Cycle Calculation of PWM: For "y" % Duty Cycle, A_VAL = (y)*100/(x)
Testing:- Output PWM waveform can be observed on DSO.
- Potentiometer input can be seen approximately on 4 LEDs in discrete range.
Exercise:
Make the connections shown below:
- Connect DSO probe +ve terminal to eMIOS0_1 PA[1] and DSO prob gnd to the gnd of the TRK-MPC5606B board.
- Similarly, Connect remaining eMIOS0 and test it.
Downloads:
eMIOS0_ADC0_TRK-MPC5606B_APDaga
Click here to see more codes for Freescale/NXP MPC56xx Family.
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Thanks and Regards,
-Akshay P. Daga