CS/EE 3720 Handout #1Spring 2005MyersLAB #1: M68HC11E1 in Single-Chip ModeLab writeup is due to your TA at the beginning of your next scheduled lab. Don’t put this off tothe last minute! In general, there will also be pre-lab work to complete before the start of the nextlab. NO LATE LAB REPORTS WILL BE ACCEPTED.1 Objectives• Gain familiarity with lab tools and solderless breadboard prototyping.• Learn to construct and debug a minimal, 68hc11-based circuit.• Learn procedures for assembling and downloading 68hc11 programs.2 Tasks1. Construct a variant of the single-chip mode circuit in fig. 2-23 of the M68HC11 ReferenceManual (Rev 6).2. Add four LEDs with current-limiting, series resistors on Port A.3. Assemble, download, and run a simple four-bit counting program.4. Experiment with modifications of the counting program.3 Tools (available in lab)• RS232/TTL converter cable (from www.kevinro.com). Available for checkout.• For PCs with D25 s erial connectors, a D25-D9 adapter is required.• Bench cable set. Available for checkout.• AS11.exe assembler (download executable from course website)• DL11.exe loader (download executable from course website)• load e1.bat batch file (download batch file from course website)• Test program to count on port A (download source from course website)Students should also bring a diskette for saving work completed during the lab.4 Parts (available for purchase in lab)Qty Description Price1 68hc11e1 microcontroller, 48-pin DIP 8.301 Crystal, 8.000 MHz 1.951 Resistor set, 10M (1 ea.), 7.5K (5 ea.), 330 (4 ea.) <1.001 Capacitor, 0.1 uF <1.004 Light-emitting diode <1.001 8-bit DIP-switch 1.401 momentary switch (optional) 1.501 22 AWG wire set <1.004.1 A note on solderless breadboardsThe ECE lab sells solderless breadboards for $9-10. These are not the best, but they should beadequate for the labs in this course. The main requirement for a good solderless breadboard is thatit makes a tight contact with 22 guage wire.We’ve had good luck with Radio Shack’s 6” ModularIC Breadboard Socket (P/N 276-174). These can be purchased on-line at www.radioshack.com. Isuspect that Standard Supply and Ra-Elco would carry good solderless breadboards as well. Onesolderless breadboard will be sufficient for the first lab.4.2 A note on wire strippersThe ECE lab keeps a few pair of wire strippers lying around the lab, though these aren’t always theeasiest to work with, and they’re sometimes in high demand. Your life will be easier if you invest inyour own pair. These can be found on-line for about $9 at http://www.wassco.com/tstripwirstr.html.I believe Ra-Elco and Standard Supply carry wire-strippers as well. Just make sure they can handle22 guage wire.4.3 A note on wire strippingIf you’re not familiar with this prototyping technique, your TAs can give you a quick demonstration.Make sure you don’t nick the wire when you remove the insulation. If you do, the end of the wirecan break in your breadboard. In some cases, these broken pieces can be very difficult to remove.If you do put a nick in the wire, just cut off the wire at that point and try again. Use red forconnections to the supply voltage and black for connections to ground.5 Procedures1. Construct the following variant of the single-mode circuit in fig. 2-23 of the reference manual(shown in Figure 1 for convenience). The pin-out for the 68hc11e1 is the same as for the68hc11e2 (see fig. 2-4 of the reference manual or p. 69 of the programming reference guide,also shown in Figure 2.) Don’t apply power until the circuit is complete and you are confidentit is correct. Fee l free to have your TA look it over first.(a) Place the 68hc11 so that pin 1 is within 2 or 3 rows of the top of the board. This willleave room at the other end for additional circuitry in later labs. Hint: Be sure the leadson the 68hc11 are at right angles to the package before forcing them into the breadboard.This may require gently bending the pins on the 68hc11 using a hard surface. Also, besure to center the 68hc11 as much as possible. You’d do well to leave 2 available columnsof sockets on the side with pin 1, and 3 available columns on the side with pin 48. Thisis because more of the additional circuitry for the single-chip mode is on this side of themicrocontroller.Figure 1: Basic single-chip mode connections.Figure 2: Pin assignments.(b) Connect the V DD and and V SS pins to the appropriate power rails on your bread-boards.(c) Use a single 0.1 uF power supply bypass capacitor across V DD and GND. Place thiscap close to the V DD pin. See RM section 2.4.1 for a discussion of power supply bypasscapacitors.(d) Use 7.5K pull-up resistors in place of the 4.7K and 10K res istors in the diagram. (There’snothing magical about 7.5K. They work, and it’s a value we have plenty of in the stockroom.) Only use pull-ups for the following: RESET*, XIRQ*, IRQ*, PD1/TXD Hint:Using wire cutters, shorten the leads on the resistors, so they can be inserted flush tothe surface of the breadboard. This will minimize risk of shorting the leads of adjacentcomponents.(e) Tie the PD1/TxD and PD0/RxD pins together with a 7.5K resistor.(f) Don’t use the MC34064 part. Just provide a normally open switch between the RESET*pin and ground. This could be a momentary switch, a DIP switch, or a piece of wire.(g) Wire both the MODA and MODB pins to ground.(h) You don’t need to wire the V RH and V RL pins.(i) Place the 8.000 MHz crystal and 10M re sistor across EXTAL and XTAL. Do not usethe 18 pf capacitors (the breadboards provide enough capacitance).(j) When you are confident that your circuit is wired correctly, but before hooking it topower, select the +6V setting on the bench power supply. Turn the power supplyoutput on and set the the voltage to 5V. Using cables from the bench cable set, connectthe power supply ground to the ground rail of the breadboard. Keeping an eye onthe power supply current, connect the breadboard positive power rail to the 5V powersupply output. If the current drawn is greater than 15 mA, remove the positive cableimmediately and inspect the circuit for shorts. We have seen instances where the powe rrails on the lab breadboards contain shorts, so don’t rule out the ”obvious” when lookingfor problems in your circuit.2. Use the oscilloscope to verify the 2 MHz system clock is running consistently (see pin 27).(a) If you are not familiar with using the oscilloscope, ask your TA for a demonstration.(b) Getting