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- We will be testing eMIOS by generating 6 PWM output simultaneously and will be changing its duty cycle in run time using switch inputs.
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% Press Switch1 -> Duty_Cycle = 20% Press Switch2 -> Duty_Cycle = 40% Press Switch3 -> Duty_Cycle = 60% Press Switch4 -> Duty_Cycle = 80%
Changelog:
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 eMIOS_Init() and set it at the end of the eMIOS_Init().]
Connections:
SWITCH No. => Port No. => Pad No. => Pin No.(144-pin LQFP package) SWITCH1 => PE[0] => PCR[64] => PIN 10 SWITCH2 => PE[1] => PCR[65] => PIN 12 SWITCH3 => PE[2] => PCR[66] => PIN 128 SWITCH4 => PE[3] => PCR[67] => PIN 129 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
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.
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:
eMIOS_Testing_TRK-MPC5606B_APDaga
Click here to see more codes for Freescale/NXP MPC56xx Family.
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Thanks and Regards,
-Akshay P. Daga