University of California at BerkeleyCollege of EngineeringEECS 150 Spring 2000Lab #9: MIDI Interface1 Objectives2 Lab Assignment3 Acknowledgements4 Check-offs (Lab #9: MIDI Interface)Pre-labLab AssignmentUniversity of California at BerkeleyCollege of EngineeringDepartment of Electrical Engineering and Computer SciencesEECS 150 Spring 2000Lab #9: MIDI InterfaceDRAFTThis lab is an official project checkpoint. It is to be completed with a project partner on your assigned project board. Project checkpoints are designed to keep you on a weekly schedule towards completion of the project. In each week’s lab, you will be asked to check-off some significant step in the design.This lab marks a transition from what we think of as “spoon-feeding” to “hand-holding.” From now in the semester, you will be given you less information on how to do the lab work. You will be making your own design decisions and figuring out your own details. You are encouraged to discuss the design problems with TAs and other students.1 ObjectivesThe objective of this checkpoint is to demonstrate the ability to recognize MIDI commands sent from a MIDI keyboard. This demonstration consists of two milestones in the development of your project:1. Correct electrical connection from the MIDI receptacle on the Xilinx board to the FPGA, utilizing an optoisolator.2. Correct functioning of a MIDI parser.The “MIDI parser” refers to a circuit that examines input bytes from a MIDI source and looks for particular patterns. This project requires a MIDI parser to recognize note-on and note- of commands. All other commands may be ignored. Refer to the project specification for details on MIDI commands and on MIDI hardware interfacing. Remember that there are two different ways to encode note-off commands.2 Lab AssignmentFirst, you should read and understand the project specification. If you have any questions about the project spec, get them cleared up early.Draw a rough, tentative board layout including all external components in your project. Aside from the EPROM that we have already installed, expect to use an optoisolator, DAC (digital-to-analog converter), amplifier, plus three IC-sized packs of discrete components (resistors, capacitors, diodes). Data sheets and wrap-ID guides for all components will be available on the course web page. The purpose of this layout is not tobe exacting but to give you an idea of physical constraints and wire lengths. Keep in mind that the Xilinx board’s wire-wrap area is limited, and that components should be positioned to minimize wire length.The physical MIDI interface requires wiring-up the Motorola MOC5009 optoisolator and associated discretes pack (2 resistors and 1 diode). These components should be connected up as per Figure 6 of the project specification. Note that the 5-pin MIDI interface in the figure is drawn as if looking into a MIDI cable (not a MIDI receptacle). The circuit will not function if the interface is wired in a mirror image.This project checkpoint requires three circuit designs for the FPGA:1. A UART transceiver, as designed in Lab #7.2. A MIDI parser that takes input from the UART and recognizes MIDI note-on and note-off commands. The brains of this circuit are a simple FSM. This is a good chance to try one-hot encoding for your state machine. An output interface for theparser is suggested in the project specification and shown below (NOTE-ON and NOTE-OFF status bits which pulse when a command is received, plus KEY and VELOCITY registers to denote command contents).3. A MIDI client that takes input from the parser and displays information about recognized commands. The KEY and VELOCITY values produced by the parser can be displayed one at a time on the 7-segment LEDs. You may use an SW5 DIP-switch to select which value to display (check the Xilinx pin assignment guide from Lab #8 for available pins and switches – some SW5 switches actually share a pin with the EPROM address lines and must be kept “open” to avoid interfering with memory). You might use the LED decimal points to indicate when a MIDI commands is received and/or what kind of command it is.Demonstrate your MIDI interface by connecting it to a MIDI keyboard in the lab and playing a few notes. Try individual notes as well as several notes at a time.3 AcknowledgementsOriginal lab by J. Wawrzynek (Fall 1994). Modifications by N. Weaver, E. Caspi.Figure 1: MIDI interface with suggested I/OUART MIDI ParserMIDI ClientOpto-isolatorSERIAL_INDRDYD[7:0]NOTE-ONNOTE-OFFKEYVELOCITYLEDs SW5-8Name: _______________________ Name: _______________________ Lab: ________4 Check-offs(Lab #9: MIDI Interface)Pre-lab- Tentative board layout TA: ________ (10%)Lab Assignment- Working optoisolator + discretes TA: ________ (20%)(visualize output on oscilloscope)- Complete MIDI interface TA: ________ (70%)Completed on time TA: ________ (-100%)Completed 1 week late TA: ________
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