Over-view of Lab. 1

1. Over-view of Lab. 1 See the Lab. 1 web-site and later lecture notes for more details

2. All embedded projects (every one built in the world) require the following • Build a “project” directory using a “development environment. • Add code to -- CODE IS RE-USED IN LATER LABS • Initialize the system • Read general purpose input signals (I part of GPIO) • Write general purpose output signals (O part of GPIO) • Initialize and use peripherals • Timers, serial interfaces to LCD screens, thermal sensors, light sensors, accelerometers, DSP programs for analysis • Build system in a controlled and testable manner • Incremental build, testing framework • Operating system (Super loop, co-operative scheduler, event driven scheduler)

3. E.g. Radio controlled voice activatedrobotic car “term” project • Set-up the processor to control the board A/D and D/A; allows capture and play-back sound. • Set-up the processor so that we can read general purpose input lines (GPIO -- switches) so we send various different commands to car. • Use the digital signal processing (DSP) part of Blackfin processor to run canned (meaning written by somebody else) frequency analysis program to recognize voice commands • Use the analysis of the sounds to output control values to a radio transmitter and control the car.

4. Main Code – pseudo code for the “voice controlled car” main( ) { // red – means canned code – green means done in Lab. 1 Launch the Analog Devices audio “echo” program – a background interrupt-driven task that is given to you – you will modify this code InitFlashASM( ); // Activate the system Flash memory without // stopping audio program which uses the Flash interface too // This enables you to write to the LED’s on the Blackfin board InitializePFInterfaceASM( ); // Activate the Push-button controller // This enables you to read switches SW1, SW2, SW3, SW4 Launch “VDK multi-threads” (separate processes) to control various processes // The VDK O/S is provided as part of the VDSP IDE Thread 1 – Captures and then stores batches of sound for analysis Thread 2 – Analyze previous stored sound for possible “commands” Thread 3 – Use previous commands to send commands to control the car Thread 4 – Check evaluation buttons for “options” (autopilot etc) Thread 5 etc

5. Another possible example project using the same code ideas We want to build a audio controller • Reuse CANNED examples provided by Analog Devices • Audio in captured using audio A/D (CODEC) • Audio out generated using audio D/A (CODEC) • Manipulate the sound quality • Modify functions that use Lab. 1 hardware interfaces • Push buttons to control audio controller operations – e.g. graphics equalizer • LED lights to display operation results and sound volume level (dancing lights)

6. Main Code – pseudo code for the “audio controller” main( ) { Launch the Analog Devices audio “echo” program – a background interrupt-driven task that is given to you – you will modify this code InitFlashASM( ); // Activate the system Flash memory without stopping // the audio program which uses the Flash interface too InitializePFInterfaceASM( ); // Activate the Push-button controller Wait for button1 to be pressed and released (ReadButtonASM() ), then play the sound at half-volume. Wait for button2 to be pressed and released, play the sound at normal volume When button3 is pressed -- Generate the extremely fascinating (but completely useless) dancing lights which change with the audio stream volume level Wait for button4 to be pressed and released, quit the program (turn off the sound and stop the processor) }

7. If we wanted to get fancy we could do the following to the audio Talkthrough program Gargling operation • Need to add a simple counter that increments by 1 every 1 / 44000 s (increments each time that an audio sample is obtained) • Use the counter to control when to turn the sound off and on every ½ s • Gargling sound is produced rather than just “turning the sound off” • For more details – see Lab. 1 from 2006.

8. Lab. 1 – Key project interfacingMicrocontroller I/O demonstration • Your group must come into the laboratory class prepared to be able to demonstrate all of the following by the end of laboratory period • You will make use of some of the code developed during the assignments. (Note assignments may be due AFTER the laboratory) • Initialize the push-button controller interface • Read, and use, a value provided by the push-button controller. • Initialize the Flash LED display interface (so that it works) • Write a value to the LED display • Read, and use, a value stored in the LED display, so you can test that you are getting the correct answer • Demonstrate tests to show that these operations work as required OPTIONAL “ENCM511 Project club” Each laboratory will provide you with enough interface information to get a component of the voice-activated radio control car to work. Extra hours of work will needed to write and test the necessary C++ code to make the interfaces operate correctly – but that can be split amongst those interested. Develop a voice activated “Windows Mobile cell-phone application”

9. Lab. Task – Does my ADSP-BF533 board work? Download audio-talk-through program • If you have not already done so, download and expand ENCM511Directory2010.zip file (used in assignment 1) so that you have the correct directory. structure and test driven development environment needed for Laboratory 1. • Download and expand the files in 10CPP_Talkthrough.zip into your AudioDemo directory. • Build an AudioDemo Blackfin project in your AudioDemo directory and add the (provided) files into the project -- compile and link. • Download the executable (.dxe) file onto the BF533 processor. • Hook up your CD or IPOD output to the CJ2 stereo input. • Hook up your ear-phones to the CJ3 stereo output. • Run the AudioDemo.dxe executable and check that the talk through program is working. • This task demonstrated your ability to build VDSP Blackfin projects and run the code (Marks for Familiarization Lab). The AudioDemo code (running in a multithread environment) forms the basis of the (optional) voice-activated radio-controlled car project.

10. Tasks of Laboratory 1 • Basic Task – develop the LED interface • Initialize the Flash memory using the Blackfin External Bus Interface Unit (EBIU) (ASM) • Initialize the memory controller of the Blackfin Evaluation Board LED’s (ASM) – can control devices and write large code • The Blackfin external bus interface unit is used to perform many “microcontroller” operations • Initialize SDRAM, audio chips etc, • Task (mainly in C++) that use the LED interface • E.g. Develop a simple counter (in C++) and display value • E.g. Write a C++ routine to write morse code values into an array • E.g. Write a routine to transfer the morse code values to the LED’s (first in C++, then ASM) • homepage.ntlworld.com/dmitrismirnov/morse-tab1.JPG

11. Task – Initialize the Programmable flag interface – 16 GPIO lines on the Blackfin • Warning – could burn out the Blackfin processor if coding is done incorrectly • You need to set (store a known value to) a number of internal registers in the Blackfin processor core. • Other processors need equivalent GPIO control methods • Most important registers • FIO_DIR – Data DIRection – set to value ?? for input **** • FIO_INEN – INterface Enable – set to value ?? for enabling the input (otherwise they will not work – power saving) • FIO_FLAG_D – Programmable FLAGData register

12. Why do you need to know how to do read (load) and write (store) on internal registers? • Flag Direction register (FIO_DIR) • Used to determine if the PF bit is to be used for input or output -- WARNING SMOKE POSSIBLE ISSUE • USE equivalent of AND instruction from ENCM369 to clear bits PF11 to PF8 to 0 for input, but must leave all other bits unchanged in value. • Read peripheral register value, use AND instruction to zero the required bits, write back value

13. Registers used to control PF pins • Flag Input Enable Register • Only activate the pins you want to use (saves power in telecommunications situation) • USE OR instruction from ENCM369 to enable (activate) pins PF11 to PF8 for input, leave all other bits in register unchanged • Read peripheral register value, use OR instruction to SET the required bits, write back value

14. Registers used to control PF pins • Flag Data register (FIO_FLAG_D) • Used to read the PF bits (1 or 0) • Need to read pins PF11 to PF8, ignore all other pins values. This requires AND and SHIFT instructions from ENCM369. • Read register value, use AND instruction to clear unwanted bits, then use masked value in code

15. Warning • The class notes remind you of the following important facts • USE equivalent of AND instruction from ENCM369 to clear bits PF11 to PF8 to 0 for input, but must leave all other bits unchanged in value. • Read peripheral register value, use AND instruction to zero ONLY the required bits, write back value • USE OR instruction from ENCM369 to enable (activate) pins PF11 to PF8 for input, leave all other bits in register unchanged • Read peripheral register value, use OR instruction to set ONLY required bits to 1, write back value These techniques were demonstrated in the tutorial this morning (Friday 24) • The lab pages WILL NOT remind you of those following important facts • This will give you the opportunity to make ‘real-life’ mistakes in the laboratory and work out how to recognize that problems are occurring and fix problems.

16. Task – Setting up the programmable flag interface • Follow the instructions carefully • FIO_DIR – direction register – write 0’s to bits 8, 9, 10, 11 – leave other bits unchanged (READ / then AND / WRITE operations) -- This sets the pins as INPUT pins • FIO_INEN – input enable register – write 1’s to bits 8, 9, 10, 11 – leave other bits unchanged (READ / then OR / WRITE operations) – This activates (turns on) the pins as INPUT pins • Other GPIO registers write 0’s to bits 8, 9, 10, 11 – leave other bits unchanged (READ / then AND / WRITE operations) • There is a test program that will enable you to check your code – provide a screen dump of test result.

17. Task – Read the switches on the front panel in “real life” • Transfer the information to the LEDs so you can demonstrate correct operations • Build Initialize_ProgrammableFlagsASM ( ) • MUST HAVE 50 pin cable connected between logic board and Blackfin for the switch values to be read correctly – otherwise switch input always reads “1”. Watch the demonstrations • Logic board power supply must be turned on (or your code will always read 1 from the switches) • What we could do – “Simple optical transmitter project” • Place a “light sensitive detector” in front of the LEDs on a “second” Blackfin station where that station is sending morse messages. • Use the output of the detector as the input to the “First Blackfin” instead of the switch, and capture the light code signals • Print out the “morse” code transmissions on the screen of the “first” station – very basic optical transmission

18. extern “C” int ReadGPIOFlags( )

19. Sign extension of input often needed

20. Using that assembly code to just wrote from C++ extern “C” int ReadGPIOFlags( ); int ReadPushButtonSwitches(void) { InitializeGPIORegisters( ); // Lab. 1 int GPIOFlagValues = ReadGPIOFlags( ); // Must happen AFTER Init( ) or // garbage results are obtained int maskToRemoveUnwantedBits = 0x0F00; // Review of ENCM369 – AND operation & and NOT && int wantedGPIOFlagValues = GPIOFlagValues & maskToRemoveUnwantedBits; return (wantedGPIOFlagValues >> 8); // bit shift operation } Returns 1 if switch 1 pressed, returns 2 if switch 2 pressed, Returns 4 if switch 3 pressed, returns 8 if switch 4 pressed, Returns 5 if switch 1 and switch 3 are pressed at the same time SW4 SW2 SW3 SW1

21. Controlling a radio controlled carusing the pushbuttons A L F R • Switch 2 pressed means go forward for 1/ 2 s • Switch 1 means turn wheels right • Switch 3 means turn wheels left • Switch 4 means accept command(Later replace switch control with music / voice control) Thus pressing switches 2, 2, 1 with 2, 2, 2, 3 with 2, 2, 2, 0, 0, 0, 0 Would cause the car to go down an “S” shape path

22. Store the commands to control a car into an array for later play-back #define STOP 0 int storeCommands[20]; int numberStopCommands = 0; int count = 0; while (numberStopCommands < 4) { command = GetValidCommand( ); if (command == STOP) { numberStopCommands ++; } else { numberStopCommands = 0; } storeCommands[count++] = command;// System crashes is more than 20 commands are entered – WHY?? – good mid term question// Is the way that viruses cause overflow of input buffer problem }

23. Get a valid command to control a car #define SWITCH4 0x8 #define ACCEPTCOMMAND SWITCH4 int GetValidCommand( ) { int command = ReadPushButtonSwitches( ); while ( (command & ACCEPTCOMMAND) != ACCEPTCOMMAND} { command = ReadPushButtonSwitches( ); } // Get here when somebody pushes switch 4 // Explain why it is a logical error if we just exit this code here // NOT fixing this error will cause “mucho-grief” in the lab – work out the problem with your lab partner return command; }

24. Task -- Tests • There needs to be software tests (E-TDD) to allow you to demonstrate that your code works correctly • Note there are test executables (.dxe) available to test out your equipment • This code can be used to test the switches and the LED interface on your board.SwitchToLED.dxe • This is the final version of my code for the “fancy” audio controllerDrSmithAudioController.dxe