ECE 4510/5530 Microcontroller Applications Week 12

Transcription

1 Microcontroller Applications Week 12 Dr. Bradley J. Bazuin Associate Professor Department of Electrical and Computer Engineering College of Engineering and Applied Sciences

2 Continuing Information PING Controller Area Network (CAN) Project 3 PLAN

3 PING Ultrasonic range sensing Dist C air Tof 2 C air T / sec m c 3

4 Controller Area Network 4

5 CAN Physical Layer Data Frames are transmitted on a two-wire common bus as CAN high (CAN_H) and CAN low (CAN_L) signals

6 Typical CAN Signaling Frame A data frame consists of seven fields: start-of-frame, arbitration, control, data, CRC, ACK, and end-of-frame. Interframe space Data Frame Interframe space or overload frame Start of frame Arbitration field Control field Data field CRC field ACK field End of frame Figure 13.2 CAN Data frame Data: 0 to 8 Bytes

7 Multiple CAN Frames 7

8 CAN Controllers The controllers handle many if not all interface issues. Software is needed to: Initialize the controller Configure the controller Select the CAN addresses to pay attention to Read the messages when received Determine message type, address, amount of data, and data Prepare a transmit message if and when required Determine message type, provide address, fill data buffers and define amount of data Handle error conditions Reset, reinitialize or just turn off.

9 Procedure for Message Transmission Step 1 Identifying an available transmit buffer by checking the TXEx flag associated with the transmit buffer. (CANxTFLG) Step 2 Setting a pointer to the empty transmit buffer by writing the CANxTFLG register to the CANxTBSEL register. This makes the transmit buffer accessible to the user. (Moves it to the foreground.) Step 3 Storing the identifier, the control bits, and the data contents into one of the foreground transmit buffers. Step 4 Flagging the buffer as ready by clearing the associated TXE flag.

10 Using multiple transmit buffers (1) void can_transmit( void ) { static unsigned int buf_addr[3] = {0xFFFF, 0xFFFF, 0xFFFF; // Check if the incoming address has already been configured in a mailbox if( can.address == buf_addr[0] ){ // Mailbox 0 setup matches our new message // Write to TX Buffer 0, start at data registers, and initiate transmission while(!(can0tflg & TXE0)){asm("nop"); CAN0TBSEL = TX0; else if( can.address == buf_addr[1] ){ // Mailbox 1 setup matches our new message // Write to TX Buffer 1, start at data registers, and initiate transmission while(!(can0tflg & TXE1)){asm("nop"); CAN0TBSEL = TX1; else if( can.address == buf_addr[2] ){ // Mailbox 2 setup matches our new message // Write to TX Buffer 2, start at data registers, and initiate transmission while(!(can0tflg & TXE2)){asm("nop"); CAN0TBSEL = TX2; else Check for existing address 10

11 Using multiple transmit buffers (2) else{ // Check if we've got any un-setup mailboxes free and use them // Otherwise, find a non-busy mailbox and set it up with our new address if( buf_addr[0] == 0xFFFF ){ // Mailbox 0 is free // Write to TX Buffer 0, start at address registers, and initiate transmission CAN0TBSEL = TX0; buf_addr[0] = can.address; Check for free address else if( buf_addr[1] == 0xFFFF ){ // Mailbox 1 is free // Write to TX Buffer 1, start at address registers, and initiate transmission CAN0TBSEL = TX1; buf_addr[1] = can.address; else if( buf_addr[2] == 0xFFFF ){ // Mailbox 2 is free // Write to TX Buffer 2, start at address registers, and initiate transmission while(!(can0tflg & TXE2)){asm("nop"); CAN0TBSEL = TX2; buf_addr[2] = can.address; else 11

12 Using multiple transmit buffers (3) else { // No mailboxes free, wait until at least one is not busy while(( CAN0TFLG & 0x07 ) == 0x00){ asm("nop"); // Is it mailbox 0? if(( CAN0TFLG & TXE0 ) == TXE0) { // Setup mailbox 0 and send the message CAN0TBSEL = TX0; buf_addr[0] = can.address; // Is it mailbox 1? else if(( CAN0TFLG & TXE1 ) == TXE1) { // Setup mailbox 1 and send the message CAN0TBSEL = TX1; buf_addr[1] = can.address; // Is it mailbox 2? else if(( CAN0TFLG & TXE2 ) == TXE2) { // Setup mailbox 2 and send the message CAN0TBSEL = TX2; buf_addr[2] = can.address; Wait until a mailbox is not busy 12

13 Using multiple transmit buffers (4) // No matches in existing mailboxes // No mailboxes already configured, so we'll need to load an address - set it up CAN0TXIDR0 = (unsigned char)(can.address >> 3); CAN0TXIDR1 = (unsigned char)(can.address << 5); CAN0TXIDR3 = 0x00; // EID8 CAN0TXIDR4 = 0x00; // EID0 CAN0TXDLR = 0x08; // DLC = 8 bytes // Fill data into buffer, it's used by any address // Allow room at the start of the buffer for the address info if needed CAN0TXDSR0 = can.data.data_u8[0]; CAN0TXDSR1 = can.data.data_u8[1]; CAN0TXDSR2 = can.data.data_u8[2]; CAN0TXDSR3 = can.data.data_u8[3]; CAN0TXDSR4 = can.data.data_u8[4]; CAN0TXDSR5 = can.data.data_u8[5]; CAN0TXDSR6 = can.data.data_u8[6]; CAN0TXDSR7 = can.data.data_u8[7]; Load the data and send CAN0TFLG = CAN0TBSEL; // clear TXE flag to send 13

14 Receive Procedure When a valid message is received at the background receive buffer, it will be transferred to the foreground receive buffer and the RXF flag will be set to 1. (CANxRFLG & RXF) The user s program has to read the received message from the RxFG and then clear the RXF flag to acknowledge the interrupt and to release the foreground receive buffer. When all receive buffers in the FIFO are filled with received messages, an overrun condition may occur. (CANxRFLG & OVRIF)

15 Using receive buffers (1) void can_receive( void ) { unsigned char flags; // Read out the interrupt flags register flags = CAN0RFLG; // Check for errors if(( flags & CSCIF )!= 0x00 ){ // Clear error flags CAN0RFLG &= ~(CSCIF); Check if CSCIF error conditions to high 15

16 Using receive buffers (2) // No error, check for received messages else if(( flags & RXF )!= 0x00 ) { // Read in the info, address & message data can.address = CAN0IDAR0; can.address = can.address << 3; temp = CAN0IDAR1 >> 5; can.address = can.address temp; // Fill out return structure // check for Remote Frame requests and indicate the status correctly if(( CAN0IDAR1 & RTR ) == 0x00 ){ // We've received a standard data packet can.status = CAN_OK; // Fill in the data can.data.data_u8[0] = CAN0RXDSR0; can.data.data_u8[1] = CAN0RXDSR1; can.data.data_u8[2] = CAN0RXDSR2; can.data.data_u8[3] = CAN0RXDSR3; can.data.data_u8[4] = CAN0RXDSR4; can.data.data_u8[5] = CAN0RXDSR5; can.data.data_u8[6] = CAN0RXDSR6; can.data.data_u8[7] = CAN0RXDSR7; can.length = CAN0RXDLR; else{ // We've received a remote frame request // Data is irrelevant with an RTR can.status = CAN_RTR; // Clear the IRQ flag CAN0RFLG &= ~(RXF); Check RXF (RTR or message) 16

17 Using receive buffers (3) else{ can.status = CAN_ERROR; can.address = 0x0001; can.data.data_u8[0] = flags; // CAN0RFLG values returned Not CSCIF or RXF. Another error, possibly an overrun error (all receive buffers full). 17

18 Project #3 Plan Old (1) Historical Project Objectives: The theme of the project is to move an object that has been placed on a conveyor belt from a start position to a specific end position. Emulation: If it was built, a physical model of the plant would include the peripherals as follows: a Start Switch, a LED indicator, a Buzzer (a small speaker), an IR (Infra Red) Emitter and Receiver Module, a H- Bridge Motor Driver Module, and a Motor Encoder Module. In the absence of a fully assembled physical model, the IR Module will be substituted by a IR LED indicator (i.e., a common LED) and a bounce-free switch (STOP#), the output signal of the Encoder Module will be provided by a Function Generator (initial frequency is 5.5KHz), and the PWM signal to drive the H-Bridge will be verified using a Logic Analyzer (initial duty cycle is 50%). All signals should comply with TTL levels. 18

19 Project #3 Plan Old (2) Historical Project Description: The system should implement the operations as follows: upon receiving the asserted START# signal (active-low), the Buzzer should sound (the frequency of the output signal f = 5.5KHz), and the LED indicator should blink six times (at the rate of 1 blink/s). The Buzzer should also be turned off when the blinking is over. Then the IR Emitter LED should be turned on. The PWM signal driving the motor should also be turned on at this point (f = approx. 30KHz, initial duty cycle = 50% to match the input frequency of 5.5 KHz). Until an active-low signal from the IR Receiver (i.e., from the STOP# switch) is detected indicating that the object on the belt has tripped the IR beam, the system should sample the frequency of the signal received from the Encoder, and respond to it by adjusting the duty cycle of the PWM signal as given in the Table below. Input frequency (KHz) Duty cycle of PWM signal (%) When the desired end position for the object is reached, the PWM signal should be turned off (duty cycle = 0%), the Buzzer should sound (at 3.5KHz), and the LED indicator should blink 10 times (at the rate of 2 blinks/s). The Buzzer and the IR LED indicator should be turned off when the blinking is over. The process should restart when the START# signal is asserted again. You are to design, simulate, build, and demonstrate the operation of the system specified above using the Adapt9S12DP512 Board in the Lab and circuits constructed on your Breadboard. 19

20 Project #3 Plan New Goals Objectives: The theme of the project is to move an object that has been placed on a conveyor belt from a start position to multiple positions as specified. Operate as in an industrial environment with warnings and indicators. Use distance sensing to provide feedback control to the conveyor. Long operations and time information for post-operation checking. 20

21 Project #3 Plan New Goals Test Hardware A 2 in. wide by 9-11 in. long conveyor. A bidirectional, geared DC motor driven by an H-bridge. Maximum RPM 60, high torque gearing with possible position overshoot. PING with ADC/Temp. for position determination. H-bridge controls (PWM and direction). Information logging capability based on Real-Time Clock/Calendar and SCI0 port Indicators and warnings based on LEDs and audio output. Operational step counter based on 5x7 display. (5530 students only) Manual conveyor operation with keypad. (5530 students only) Step learning sequence based on keypad. 21

22 Project #3 Plan Dependence Progress in getting the hardware acquired and built. 22

23 Data Logging Collection of sensor information Inclusion of a time and data stamp with data Non-volatile storage Once data is collected, it should never be lost until intentionally deleted. 23

24 Useful Textual Formats A common file format is CSV comma separated values. From In practice the term "CSV" refers to any file that: 1. is plain text using a character set such as ASCII, Unicode, EBCDIC, or Shift JIS, 2. consists of records (typically one record per line), 3. with the records divided into fields separated by delimiters (typically a single reserved character such as comma, semicolon, or tab; sometimes the delimiter may include optional spaces), 4. where every record has the same sequence of fields. Within these general constraints, many variations are in use. Therefore "CSV" files are not entirely portable. Nevertheless, the variations are fairly small, and many implementations allow users to glance at the file (which is feasible because it is plain text), and then specify the delimiter character(s), quoting rules, etc. If a particular CSV file's variations fall outside what a particular receiving program supports, it is often feasible to examine and edit the file by hand or via simple programming to fix the problem. Thus CSV files are, in practice, quite portable. 24

25 CSV File Access MATLAB M = csvread(filename); csvwrite(filename,m); Excel Will both read and write spread sheet information as CSV files 25

26 Text Files as Data Logs LT C3A LT C3E LT C39 LT C3E LT C3D LT C38 LT C3D LT C3B LT C38 LT C3A LT C39 LT C3B LT C3D LT C3E LT C3C LT C3C LT C3D LT C34 LT C39 LT C33 LT C38 LT C3C LT C3B LT C3A LT C39 LT C39 LT C38 LT C36 LT C3A LT C36 LT C36 LT C3B LT C3B LT C3A LT C31 LT C39 LT C3C LT C3A AD EC098 AD F4ABA AD FE AD F9DFE AD F1EC2 AD F109A AD EC6D4 AD FDBA6C AD EC2E2 AD FCF1A AD FB10A AD F0E5C AD EC294 AD EF91A AD EC762 AD FD6922 AD FE31E AD AD E850A AD F0B24 AD F6118 AD FB552 AD E5D68 AD FD36AE AD F424 AD AD AD AD FD7FEC AD AD D1E60 AD F434 AD E846 AD E AD E1BA AD AD F3A AD CD8C AD E3A AD FD3FAE AD AD AD E30 AD F96 AD B8 AD E750 AD F0 AD FD2050 AD AF0 AD AD EEC0 AD C04 AD F18 AD A70 AD C1C11A AD FD4A7E AD AE68C AD AD E AD AD FD6AC8 AD AD D4B1C AD D4A2A ISH 00 FFF8D764 ERR 00 06E00000 ERR 01 04F00000 ERR ERR 03 04F00000 ERR ERR 05 06F00000 ERR ERR ERR ERR ERR ERR D49E6 ERR ERR ERR ERR ERR ERR ERR ERR ERR 05 06F

27 Example Translation LT AFA LT AFC LT AFA LT AFC LT AFB LT AFA LT AFB LT AFB LT AFA LT AFA LT AF LT AFC LT AFB LT AFD LT AFA LT AFC LT AFB min LT AF max LT AF diff

28 Example Translation LT AFA LT AFC LT AFA LT AFC LT AFB LT AFA LT AFB LT AFB LT AFA LT AFA LT AF LT AFC LT AFB LT AFD LT AFA LT AFC LT AFB min LT AF max LT AF diff