FRI DEC 12
finals study guide txt
bombs source code directory

MON DEC 8
gdb notes pdf txt

FRI DEC 5
bomblab (ass'n 11) pdf
bombs directory
due fri dec 12

WED DEC 3
adv cpu topics txt
pls rtn kit on friday! pdf
pls do course eval! html

MON DEC 1
assignment 10: caches pdf
  due fri dec 5

FRI NOV 14
assignment 9: pipe optimization pdf
  files tar

FRI NOV 7
assignment 8: cpu research pdf

TUE NOV 4
take-home midterm due Wed Nov 5 pdf

MON NOV 3
assignment 7 practice pdf

FRI OCT 31
assignment 7: y86 and seq pdf due Nov 7
  assignment7.tar tar
  ass'n 5 back
  ass'n 6 back
  ass'n 6 answers
  ISA slides pdf
  SEQ slides pdf

WED OCT 22
midterm (open data sheets, ass'n 6 not included)

MON OCT 20
midterm review
  notes txt

WED OCT 15
assignment 6b: mapping a RAM pdf
  due Oct 20 (along with Ass'n 6)
  6.270 hardware pdf
  Cypress 6264 8K RAM pdf
  Handy Board schem gif
  68HC11 big manual pdf

FRI OCT 10
assignment 6: address decoding pdf
  due Oct 17
  expanddemo.s
  mystery5000.rel

MON OCT 6
assignment 5 pdf
  due Oct 15
  README FIRST!
  BootLoad.java
  ReadRel.java
  Serial.java
  serialxmit.s
  BootTerm.java
  BootTermSafe.java
  analogdemo.s

MON SEP 29
intro to 6811 pdf
m68hc11e manual pdf
assignment 4 pdf html
  due Oct 6
  java setup html
  HC11Boot.java
  Serial.java
  beep.s

WED SEP 24
garage state machine pdf

MON SEP 22
logic implementation of eqns pdf tiff

FRI SEP 19
assignment 3 pdf html due Sep 29
logic eqn reading from Fletcher no link

MON SEP 15
schematic hints html pdf
mystery hints pdf

FRI SEP 12
transistor reading from horowitz/hill no link
pp 117-141 from Tanenbaum no link

MON SEP 8
assignment 2 pdf due Sep 15
data sheets html
uml305dev html pdf
parts list pdf

WED SEP 3
assignment 1 pdf due Sep 8

THE UML 91.305 DEVELOPMENT BOARD

INTRODUCTION

The UML 91.305 Development Board provides a collection of useful features for basic digital logic circuit prototyping:

• +5v power supply based on 4 AA cells
• logic probe circuit with red/green indicators for logic high and logic low
• 8 LEDs for monitoring signals
• 8 switches (four DIP, four pushbutton) for generating high and low signals
• serial line voltage converter circuit for interfacing from PC serial ports to chip-level serial signals
• piezo beeper for listening to oscillating signals in the audible range

This document provides an overview of the 91.305 Development Board (UML305DEV). A separate document provides assembly instructions.

FEATURES

This section explains the features of the Development Board in detail. Please refer to the schematic diagram on the last page of this document for additional information.

Power Supply

The power supply is based on 4AA cells, which generate a nominal 6 volts. (This voltage will be somewhat higher when the cells are brand new, and will fall as the cells discharge over use.)

To adjust the voltage to a better range for use with digital logic, the battery voltage is run through diode D1 (a 1N4001 diode). This provides a nominal 0.6v drop, putting the useful battery voltage in the 5.5v range. This is of course higher than the nominal 5.0v specified by digital logic, but within the allowable range.

The 1N4001 diode also acts as a current limit in case of short circuit (power being connected to ground by a wire). In this instance, the diode will get quite hot, and may even fail, but it will prevent dangerously large amounts of current from flowing.

Please DO NOT USE NICAD BATTERIES with the UML 305 Dev Board!! Only use alkaline batteries. Nicad batteries can produce dangerously large amounts of current when shorted.

The Vcc and ground power outputs are available along the right hand connector. The top four positions are Vcc taps; the lower four positions are ground taps. The main power switch SW6 controls power on/off. When power is switched off, both internal board power and external power are removed.


Logic Probe Circuit

A logic probe circuit is located in the lower left corner of the board. The probe signal input is located along the vertical connector strip along the right edge of the board, labeled probe.

The red LED lights when the probe signal is logic high (4.4v or greater).

The green LED lights when the probe signal is logic low (0.6v or less).

If no signal is applied, or if the signal is between 0.6v and 4.4v, neither LED will light.

The circuit is implemented with transistors Q1 – Q4 and the associated resistors.

Q2 and Q3 control the logic high LED. If a signal within 0.6v of Vcc (e.g., 4.4v or greater) is applied, then transistor Q2 turns off. This allows R7 to turn on transistor Q3, and the red LED is lit.

A similar circuit controls the green LED. A signal of 0.6v or less will cause Q1 to turn off. This allows R8 to enable Q4, and the green LED lights.


Eight General Purpose Status LEDs

LEDs 1 through 8 are general purpose status LEDs. Inputs to the LEDs are provided along the right side connector strip. A +5v signal input lights the corresponding LED.

Resistor network RN1 provides 1K current-limiting resistors for each LED.


General Purpose Switches

Switches SW1 through SW4 are four pushbutton switches which generate 0 or 5v signals. Switch SW5 is a 4-position DIP slide switch which generates additional 0 or 5v signals. The switch outputs are located along the right side connector strip.

When a switch is closed (pressed if a pushbutton, or “on” if a DIP slide switch), a 5v output is generated.

When the switch is open, a 0v output is generated.

The 0v outputs are created with 1K resistors to ground (from resistor network RN2). This means that only a limited amount of current can flow through the resistor (5 mA). This is more than enough to ground a digital input, but can’t be used for high current applications.

The 5v outputs are created with the switch closure connecting directly to the Vcc supply. Therefore arbitrary amounts of current can be sourced. The switch outputs are ideal for lighting the status LEDs directly.


Serial Line Converter

The UML305DEV board includes a DB9 female connector suitable for attachment to a PC serial port using a standard DB9F-DB9M straight through cable. The serial signals are converted from the PC voltage standard (–10v for logic high, +10v for logic low) to the chip level (aka “TTL”) voltage standards (+5v for logic high, 0v for logic low). These TTL level signals are available on the right side connector strip at the two points labeled rcv and xmit.

The rcv line is an output of the UML305DEV board and should be connected to the serial receive input of the TTL device (e.g., the 68HC11 microprocessor). It’s the same signal that would be considered the PC’s serial transmit output, only converted from PC to TTL voltage levels.

The xmit line is an input to the UML305DEV board and should be connected to the serial transmit output of the TTL device. It is converted and then guided to the PC’s serial receive input.

Little arrowheads next to the rcv and xmit pins should help clarify which signal is input and which is output to the dev board.

The serial line conversion is done by the Maxim MAX232 serial transceiver chip. The chip uses capacitors to create the +10v and –10v voltages that are supplied to the PC.


Piezo Beeper

The large round piezo beeper will produce clicks and tones when an oscillating signal is applied to its input (labeled piezo on the right side connector strip).

The piezo input is fairly high impedance, meaning very little power is required to generate sound.