EECS 192: Mechatronics Design Lab

Transcription

1 EECS 192: Mechatronics Design Lab Discussion 11: Embedded Software GSI: Varun Tolani 4 & 5 April 2018 (Week 11) 1 Intro 2 Timers 3 Communication & UART 4 Structuring Your Code Ducky (UCB EECS) Mechatronics Design Lab 4 & 5 April 2018 (Week 11) 1 / 24

2 Intro Ducky (UCB EECS) Mechatronics Design Lab 4 & 5 April 2018 (Week 11) 2 / 24

3 Intro What does all this mean? Ducky (UCB EECS) Mechatronics Design Lab 4 & 5 April 2018 (Week 11) 3 / 24

4 Intro Ducky (UCB EECS) Mechatronics Design Lab 4 & 5 April 2018 (Week 11) 4 / 24

5 Timers Timers Ducky (UCB EECS) Mechatronics Design Lab 4 & 5 April 2018 (Week 11) 5 / 24

6 Timers What are some of the different kinds of timers? Periodic Interrupt Timer (PIT) Flexible Timer Module (FTM) Programmable Delay Block (PDB) Real Time Clock (RTC) Ducky (UCB EECS) Mechatronics Design Lab 4 & 5 April 2018 (Week 11) 6 / 24

7 Timers When do we use these timers? Periodic Interrupt Timer (PIT) Running functions periodically (i.e. control) Flexible Timer Module (FTM) Running functions periodically (i.e. control) Generating PWM Programmable Delay Block (PDB) Delaying for a specific amount of time Real Time Clock (RTC) Tracking execution time (i.e. get curr time) Ducky (UCB EECS) Mechatronics Design Lab 4 & 5 April 2018 (Week 11) 7 / 24

8 Timers PIT (Review) # define PIT_IRQ_ID PIT0_IRQn # define PIT_SOURCE_CLOCK CLOCK_GetFreq ( kclock_busclk ) // config ->enablerunindebug = false ; PIT_GetDefaultConfig (& pitconfig ); PIT_Init (PIT, & pitconfig ); /* Set timer period for channel 0 */ PIT_SetTimerPeriod (PIT, kpit_chnl_0, USEC_TO_COUNT (500000U, PIT_SOURCE_CLOCK )); //.5s timing /* Enable timer interrupts for channel 0 */ PIT_EnableInterrupts (PIT, kpit_chnl_0, kpit_timerinterruptenable ); /* Enable at the NVIC */ EnableIRQ ( PIT_IRQ_ID ); PIT_StartTimer (PIT, kpit_chnl_0 ); Ducky (UCB EECS) Mechatronics Design Lab 4 & 5 April 2018 (Week 11) 8 / 24

9 Timers FTM as a timer (prescaler) # define BOARD_FTM_BASEADDR FTM0 # define BOARD_FTM_IRQ_NUM FTM0_IRQn # define BOARD_FTM_HANDLER FTM0_IRQHandler # define FTM_SOURCE_CLOCK ( CLOCK_GetFreq ( kclock_busclk ) /4) FTM_GetDefaultConfig (& ftminfo ); ftminfo. prescale = kftm_prescale_divide_4 ; /* Initialize FTM module */ FTM_Init ( BOARD_FTM_BASEADDR, & ftminfo ); FTM_SetTimerPeriod ( BOARD_FTM_BASEADDR, USEC_TO_COUNT (1000U, FTM_SOURCE_CLOCK )); // Enable Interrupts FTM_EnableInterrupts ( BOARD_FTM_BASEADDR, kftm_timeoverflowinterruptenable ); EnableIRQ ( BOARD_FTM_IRQ_NUM ); FTM_StartTimer ( BOARD_FTM_BASEADDR, kftm_systemclock ); Ducky (UCB EECS) Mechatronics Design Lab 4 & 5 April 2018 (Week 11) 9 / 24

10 Timers FTM There are 4 FTM s s (0-3) Each FTM has up to 8 channels (think h bridge or even brushless motor control) Each FTM runs is locked to 1 frequency (but not duty cycle!!!) FTM allows you to use a prescaler (to count very slowly without overflow) Ducky (UCB EECS) Mechatronics Design Lab 4 & 5 April 2018 (Week 11) 10 / 24

11 Timers FTM for PWM (review) # define BOARD_FTM_BASEADDR FTM0 # define BOARD_FTM_IRQ_NUM FTM0_IRQn # define BOARD_FTM_HANDLER FTM0_IRQHandler # define FTM_SOURCE_CLOCK kclock_busclk ftmparam. chnlnumber = BOARD_FTM_CHANNEL ; ftmparam. level = PWM_LEVEL ; ftmparam. dutycyclepercent = init_duty_cycle ; ftmparam. firstedgedelaypercent = 0U; FTM_GetDefaultConfig (& ftminfo ); ftminfo. prescale = kftm_prescale_divide_128 ; // Optional for slow PWM FTM_Init ( BOARD_FTM_BASEADDR, & ftminfo ); // Dont Need Interrupts Here!!! FTM_SetupPwm ( BOARD_FTM_BASEADDR, &ftmparam, 1U, kftm_centeralignedpwm, freq_hz, FTM_SOURCE_CLOCK ); FTM_StartTimer ( BOARD_FTM_BASEADDR, kftm_systemclock ); Ducky (UCB EECS) Mechatronics Design Lab 4 & 5 April 2018 (Week 11) 11 / 24

12 Communication & UART Communication and UART Ducky (UCB EECS) Mechatronics Design Lab 4 & 5 April 2018 (Week 11) 12 / 24

13 Communication & UART UART Universal Asynchronous Reciever and Transmitter Asynchronous Digital Data Transfer Protocol Data format and Data speed (baud rate) are configurable Used for serial communication (USB, ethernet, etc.) Transmits data as byte string User chosen baud rate (bits/second) Ducky (UCB EECS) Mechatronics Design Lab 4 & 5 April 2018 (Week 11) 13 / 24

14 Communication & UART UART UART Tx- Transmit, Rx- Receive, G- Gnd (only need 3 pins for UART data transmission) Ducky (UCB EECS) Mechatronics Design Lab 4 & 5 April 2018 (Week 11) 14 / 24

15 Communication & UART UART Baud Rate Baud = bits/second Some common baud rates are 9600, 38400, Ducky (UCB EECS) Mechatronics Design Lab 4 & 5 April 2018 (Week 11) 15 / 24

16 Communication & UART UART Bluetooth on K64F We can just plug in our bluesmirf chip directly to the K64F! Ducky (UCB EECS) Mechatronics Design Lab 4 & 5 April 2018 (Week 11) 16 / 24

17 Communication & UART Telemetry Telemetry Why Telemetry Necessary for checkpoint 9 and race 1/2 Invaluable for real time debugging Telemetry uses UART! Can do asynchronous communication Floating Point! Easy to switch between USB & Bluetooth Ducky (UCB EECS) Mechatronics Design Lab 4 & 5 April 2018 (Week 11) 17 / 24

18 Communication & UART Telemetry Our Telemetry System telemetry uart.c (in telemetry skeleton code) # define DEMO_UART UART0 # define DEMO_UART_CLKSRC UART0_CLK_SRC # define DEMO_UART_CLK_FREQ CLOCK_GetFreq ( UART0_CLK_SRC ) # define DEMO_UART_IRQn UART0_RX_TX_IRQn # define DEMO_UART_IRQHandler UART0_RX_TX_IRQHandler void init_uart ( void ){ uart_config_t config ; /* * config. baudrate_bps = U; * config. paritymode = kuart_paritydisabled ; * config. stopbitcount = kuart_onestopbit ; * config. txfifowatermark = 0; * config. rxfifowatermark = 1; * config. enabletx = false ; * config. enablerx = false ; */ UART_GetDefaultConfig (& config ); config. baudrate_bps = U; config. enabletx = true ; config. enablerx = true ; } UART_Init ( DEMO_UART, &config, DEMO_UART_CLK_FREQ ); UART0 routes to USB if plugged in! For bluetooth need to use UART corresponding to PTC14/15 Ducky (UCB EECS) Mechatronics Design Lab 4 & 5 April 2018 (Week 11) 18 / 24

19 Communication & UART Telemetry Our Telemetry System (as of April 3) Data flows 1 way Ducky (UCB EECS) Mechatronics Design Lab 4 & 5 April 2018 (Week 11) 19 / 24

20 Communication & UART Telemetry Tips for Telemetry Get telemetry working via usb first Use the same baud rate on your laptop, K64, and bluetooth chip (will not work if you ignore this) The bluetooth chips come preconfigured from previous years to run at a certain baud rate (usually 9600, 38400, or ). You can change this if needed. Using telemetry with a slower baud rate is recommended (9600 or 38400). Logging too many variables (especially waterfall plots) will slow down your cpu. Known Telemetry Issues Can only transfer 32bit values as of now Data only flows 1 direction Blocking writes used Ducky (UCB EECS) Mechatronics Design Lab 4 & 5 April 2018 (Week 11) 20 / 24

21 Structuring Your Code Structuring Your Code Ducky (UCB EECS) Mechatronics Design Lab 4 & 5 April 2018 (Week 11) 21 / 24

22 Structuring Your Code Code Structure 1 Closed Loop Control & Telemetry int main (){ init_pit (freq, pit_handler ); while (1) { telemetry. do_io (); } } void pit_handler (){ estimate_velocity (); find_line (); calculate_steering_error (); calculate_velocity_error (); apply_steering_control (); apply_velocity_control (); } Ducky (UCB EECS) Mechatronics Design Lab 4 & 5 April 2018 (Week 11) 22 / 24

23 Structuring Your Code Code Structure 2 Closed Loop Control & Telemetry int main (){ init_pit (freq, pit_handler ); while (1) { PRINTF ( debugging \r\n ); telemetry. do_io (); } } void pit_handler (){ estimate_velocity (); find_line (); calculate_steering_error (); calculate_velocity_error (); apply_steering_control (); apply_velocity_control (); } Why might this be a bad idea? Ducky (UCB EECS) Mechatronics Design Lab 4 & 5 April 2018 (Week 11) 23 / 24

24 Structuring Your Code Code Structure 3 Closed Loop Control & Telemetry int main (){ init_pit (freq, pit_handler ); init_idle_task (); while (1) { SPRINTF ( debugging \r\n ); telemetry. do_io (); } } void idle_task (){ PRINTF ( queue. pop ()); } void pit_handler (){ estimate_velocity (); find_line (); calculate_steering_error (); calculate_velocity_error (); apply_steering_control (); apply_velocity_control (); } Ducky (UCB EECS) Mechatronics Design Lab 4 & 5 April 2018 (Week 11) 24 / 24