Oricom Technologies OOBOT40-3 Technical Info

Return to: OOBOT40-3 page. OOBOT40-3 Controller Technical Info

General Features

Voltage regulator
---- 5v, 1-1.5A, 7805-equiv TO-220, with heat-sink.
---- +5v power-good Led.
CPU - OOPic II+ microcontroller in 40-pin DIP package
---- main oscillator - 20 Mhz crystal.
---- Reset switch
I²C interfaces
---- 5-pin PRG "local buss" header for OOPic parallel programming (Reset-5v-Sclk-gnd-Sdat).
---- (NOTE that progamming will normally be done via serial port conn P1).
---- 5-pin I²C "DDE buss" header for OOPic-OOPic networking.
CPU Port usage
---- A = up to 7 analog signals and general digital I/O
---- B = 8 lines for servo control and general digital I/O
---- C = RS-232, I²C, PWM to h-bridge (speed control), SW1 + Led L2
---- D = h-bridge and nMOSFET inverter control, plus 2 general digital I/O
---- E = 3 lines for analog signals and general digital I/O
EEPROM
---- layout for 8-pin I²C serial EEPROM chip, up to 32KB (eg, 24C256).
---- used for non-volatile program storage.
---- jumpers J1 - J4 allow the EEPROM to be controlled by cpu pins RA4/RA5 for OOPic operation, or by the PIC internal I²C buss [cpu pins RC3/RC4].
RS-232 comms
---- MAX232-type chip with 2 transmit-receive channels, one is connected to cpu internal UART at RC6/RC7, and one is spare.
---- spare channel can be used for serial LCD, comm to another board, etc.
---- interface via DB09-F conn P1 for chan-1, and P2 for chan-2.

---- 2nd RS-232 channel can be used for daisy-chaining OOBOT40-3 boards.

- Uses of Prototyping Area -
pullups, pulldowns, series R's, zener diodes, digital chips, analog chips, opAmps, EEPROMs, speaker amps, bipolar inverters, MOSFET drivers, pushbutton switches, LEDs, sensor conditioning.

Miscellaneous
---- pushbutton SW1 + Led L2 share one cpu I/O line (RC0).
---- PZ piezo layout - accommodates both piezo and magnetic beepers
Prototyping Area
---- large 10x9 hole prototyping area.
---- allows custom circuitry to be added for cpu pins RA0-RA5, RE0-RE2.
---- proto area laid out for ease of build-up, with +5v and ground busses aligned for easy addition of DIP chips, pullups, pulldowns, series R's, etc.
---- can handle up to one 18-pin or two 8-pin DIP chips.
External Connections

---- all headers 0.1" spacing, DIL for HDR1 in proto area, and TIL for HDR2.

Having a ground pin next to every signal pin on the headers makes it extremely easy to wire sensors and effectors in such a way as to minimize inductive wiring loops and associated noise problems, since every line can use parallel, twisted, or shielded wires. This way sensors can be shielded against noise pickup, and motors + servos will radiate less EMI.

---- outer rows = all grounds on peripheral headers.
---- usable with DIL ribbon cables or header receptacles with 2 or more pins.
---- layout convenient for making multiple 2-wire (signal+gnd) connections.
---- HDR1 = 2x10 DIL - analog & digital I/O.
---- HDR2 = 3x14 TIL - digital I/O or servos, plus +S power -(separately configurable halves).
---- P1 - DB09/F connector for main RS-232 channel to OOPic UART.
---- P2 - 3-pin, 3.5 mm terminal block for RS-232 port #2.
---- P3 - 6-pin, 3.5 mm terminal block for h-bridge outputs, plus +M power.
---- P4 - 3-pin, 3.5 mm terminal block for MOSFET inverter outputs.

Servo Control - HDR2

provides for direct connection of up to 10 Futaba-wired servos (signal-pwr-gnd).
+S connection allows for external servo power input connection.
provides for mix and match of digital I/O or servo drive.
Header rows:
---- inner = digital in/out signals.
---- middle = +S or +5v power buss.
---- outer = all grounds.
---- 2 halves of HDR2 can be separately configured with middle row either +S power (for servos) or +5v power (for driving external sensors, etc).

H-Bridge Channels - conn P3

can drive up to 4 uni-directional or 2 bi-directional motors.
can drive 1 unipolar or bipolar stepper motors, or general hi-current loads.
L298N h-bridge chip provides 4 separate push-pull drive channels, up to 36v and 2-Amp each.
large heatsink on h-bridge.
+M power provided from off-board.
input lines to h-bridge chip controlled by cpu port D0-D3.
enable lines to h-bridge chip controlled by cpu PWM channels RC1 and RC2.

MOSFET High-Current Driver Channels - conn P4

circuitry can drive LEDs, relays, motors, solenoids, etc.
Q1, Q2 are logic-level n-channel MOSFETs configured as inverters, loads up to 5+ Amp.
outputs controlled by cpu port RD4, RD5.
load power provided from off-board.
external clamping diodes must be used when driving inductive loads.

Safety and Transient Suppression Features

all cpu I/O lines have series protection resistors and pulldown terminations.
Motor Transient Suppression:
---- L298 h-bridge chip with external clamp diodes.
---- reservoir cap and hi-V bypass cap, plus tranzorb diode, on +M line.
Power Buss Isolation:
---- 3 separate power busses total - +5v (logic), +S (servos), and +M (motor).
---- Servos can be configured for operation off +5v buss or external +S power on HDR2.
---- h-bridge loads operate off external +M power on conn P3.
+M and +S ground busses physically and electrically isolated from microcontroller gnd buss, with 1-point connection via ferrite or inductor Z1.

Power

input power 8 - 15 vdc, up to 1.5 Amp.
power for servos is provided from off-board, via headers, normally 4.8 - 6 vdc at approx 300 mA per connected servo.
power for Mosfet loads and motors is provided from off-board, via headers, up to 40v allowable.

Physical

4.1" x 3.0" (104 x 76 mm), industrial-quality double-sided FR4 pcb with heavy buss traces, plated-through holes, solder masks and silk-screens.
mounting hole in each corner (#4 screw).

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