EAS FINGER BOARD II 68HC11 Single Board Computer Ver. 11/24/03 Embedded Acquisition Systems 2517 Cobden Drive Sterling Heights, MI 48310 http://www.embeddedtronics.com email sales@embeddedtronics.
EAS FINGER BOARD was created as a small compact general purpose embedded controller to be used for robotics, data logging, smart instruments, and custom control applications. It can run “Interactive C” and emulates many of the hardware functions of “Handy Board” by MIT. Motor functions as well as push buttons were left out of the design to keep it small, simple and versatile. All functions of the “Handy Board” can be added via expansion board, circuits of older “Rug warrior” designs as well.
Step 3 Install the 52pin PGA IC socket for U4. Observe proper orientation for pin 1 before soldering. Step 4 Install the resistors R2, R3, R5, R6 and R8. Bend the resistor so that it may stand end up on the PCB. R2, R5, R6, R8 - 10K ohm R3 - 1 Meg ohm Step 5 Install resistor R4. This is a 47K inline sip resistor. Observe proper orientation for pin 1 before soldering. Pin 1 is usually marked with a dot. R4 - 47K ohm inline sip resistor. Part#10-1-473 Step 6 Install capacitor C3 and C4.
JP6 - Header 2x2 JP10, JP12, JP13 - installed as one Header 3x2 JP14 - Header 3x2 JP18 - Header 2x1 JP19 - Header 2x1 Note: If you have the one piece Finger Board with attached Communications board, you do not have to install JP14. There are already pcb traces connecting JP14 to JP15. You can omit JP6 and use the solder pads J1 and J2. By bridging solder pad J1, A/D ref input VRH will be connected to VCC. Bridging solder pad J2 will connect A/D ref input VRL to ground.
Step 13 Bridge solder Pad J5 using a small blob of solder. This will connect the SRAM supply to VCC. J5 is located on the bottom side of the board, near JP4. Note: If you plan to use a standard 256kbit SRAM memory chip and not a Dallas battery backed memory module, do not bridge solder pad J5. See step 22 for optional external SRAM battery backup. Step 14 You should wash and clean the completed board before installing U3 and U4. We use water soluble flux solder here at EAS. This permits easy board cleaning.
backwards, the communications board will not operate. Place the cathode side of the LED to line up with the silkscreened bar on the PCB. R7 - 1K ohm D1 - HLMP1790 LED Note: The LED is rated for 2ma. If a higher current model is substituted, the Communications board will not work. You can decide not to install the LED, since it just indicates download mode. The download mode will also be indicated on your computer screen while Interactive C is sending out the pcode.
The Finger Board II was designed to allow our LCD module to mount directly on top using a header and socket with the communications board attached. Optional parts installation Step 22 SRAM Battery Backup If you plan to use a standard 256kbit SRAM memory chip and not the Dallas battery backed memory module, install diodes D4 and D5. Place the cathode side of the diodes to line up with the silkscreened bar on the PCB. Do not bridge solder pad J5.
PARTS LIST FOR FINGER BOARD II Bill Of Materials, all parts can be found from Radio Shack, Digikey, JDR and Jameco. All resistors ½ Watt or less. All similar parts found on “Handy Board” can also be used on Finger Board.
CONNECTING TO THE FINGER BOARD 9
Headers are counted in the same pattern as drawn on the schematic diagram. When possible we have placed the label closest to pin 1 on the printed circuit board. Pin 1 is marked with a square pad. See silkscreen top view drawing. JP1 is the DC input connector used to power the Finger Board. You can use any voltage from 7 to 18 volts. Pin 1 2 Function +Battery input ground JP2 is an Interactive C compatible LCD interface.
JP7 is the 68HC11 8-bit A/D analog input port. Input voltages between 0 and 5volts can be applied to the A/D. Grounds are provided for each analog input. Pin 1 3 4 6 7 9 11 13 Function AN0 AN1 AN2 AN3 AN4 AN5 AN6 AN7 Pin 2 3 5 6 8 10 12 14 Function ground ground ground ground ground ground ground ground JP8 is PORT A on the 68HC11. This is an 8-bit digital input/output port. Reading the "M68HC11 Reference Manual", by Motorola will give information on how to utilize this port.
JP10 is a dedicated header for a Sharp IR receiver when running Interactive C. Pin 1 2 Function Sharp IR receiver (68HC11 output pin PA2) Ground JP11 is useful for external interrupt requests. Pin 1 3 Function XIRQ\ IRQ\ Pin 2 4 Function ground ground JP12 is a dedicated header for a Piezo beeper or speaker when running Interactive C. Pin 1 2 Function + Piezo beeper or speaker (68HC11 output pin PA3) ground JP13 is a dedicated header for an Infrared transmitter when running Interactive C.
JP18 is the MODB select. By placing a jumper on JP18, this will enable you to change the reset vector from 0xBFFE, 0xBFFF to 0xFFFE,0xFFFF. It is used in conjunction with the Download switch (S1) on the Communications board. Pressing the Download switch pulls the MODA line low (open).
RUNNING INTERACTIVE C Interactive C (IC) is a simple to use C compiler for the 68HC11. The freeware version of IC can be downloaded from MIT’s FTP site at ftp://cherupakha.media.mit.edu/pub/projects/6270/interactive-c along with a manual that can be printed out for reference. There is also more information on the “Handy Board” web page on how to use IC. To use the Finger Board you need to connect the serial port of your PC to the serial connector P1 of the Finger Board Communications board.
USING OTHER COMPILERS AND PROGRAMS The Finger Board was designed to take advantage of the many public domain software available on the web as well as any commercial compilers. There are links on our web site to freeware and shareware compilers and programs that can be downloaded and used to write programs for the Finger Board II. Check out our related sites page for links to commercial compilers To use certain compilers, you must be aware of the reset vector location.
FREQUENTLY ASKED QUESTIONS (FAQ) Please check our web site for the latest version of the Finger Board FAQ. TROUBLE SHOOTNG If you have purchased the assembled Finger Board, it is fully tested and operational before shipping. If it fails to function properly, inspect the board for obvious physical damage. If there is damage, please contact us for replacement. The most common problems are improperly configured communications parameters or attempting to use the wrong COM port on the PC.
Silkscreen Top View. Pin 1 on all headers are indicated by the square pad.
SPECIFICATIONS: Motorola 68HC11 CPU A0, A1, A8, E2, or E9 versions can be used. 256kbit (32Kbyte) Dallas 10 year battery-backed memory module, no need to use EPROMs or slower EEPROMs. Compact size 2” X 2.85”. Interactive C compatible LCD interface. Network capable, Serial Peripheral Interface (SPI). Jumper selectable reset address. Reset vector can be located at 0xFFFE,0xFFFF or 0xBFFE,0xBFFF improved over the Handy Board.
STANDARD LEGAL STUFF Although all of the circuits and projects provided have been thoroughly tested by Embedded Acquisition Systems (EAS). We cannot take responsibility for the circuits, nor will we take any responsibility for anything happening as a result of using any of our designs. PERFORMANCE INFORMATION: Performance tests and ratings are measured using specific computer systems and/or components and reflect the approximate performance of EAS products as measured by those tests.
PARTS LIST FOR FINGER BOARD II Bill Of Materials, all parts can be found from Radio Shack, Digikey, JDR and Jameco. All resistors ½ Watt or less. All similar parts found on “Handy Board” can also be used on Finger Board.
