ETC 550

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Eddie Control Board with Power Connector (#28993)
Eddie Control Board PCB (#550-28990)
The Eddie Control Board provides a complete single-board solution to control the Eddie Robot Platform
(28992). Designed to be flexible and expandable, the Eddie Control Board is also well suited for other
mobile robot platforms. While the board has a wide input voltage range, it is primarily targeted to
12 VDC battery-powered applications.
The heart of the Eddie Control Board is the Propeller P8X32A microcontroller. The Propeller chip’s eight
32-bit cores provide incredible power and flexibility. The board includes high-current motor drivers, an
eight-channel 10-bit ADC, and access to lots of digital I/O. Multiple regulated power supplies (12 V, 5 V,
and 3.3 V) and three switchable auxiliary power ports support optional accessories for your robot.
This document provides details and specifications about the Eddie Control Board hardware only. For
additional information and for details about the latest firmware, go to www.parallax.com/eddie.
Features
 Powered by the Propeller P8X32A with
eight 32-bit cores




Integrated high-current motor drivers

Three auxiliary power ports provide
switchable battery voltage for
accessories
Key Specifications
 Power requirements:
Main board operating voltage
(VCCMAIN) 6.75 to 18 V;
Motor driver operating voltage
(VCCMOTORS) 5.5 to 16 V
Eight-channel 10-bit ADC
Up to 16 general purpose digital I/O
On-board regulated power supplies for
12 V, 5 V, and 3.3 V.

5 A auxiliary power fuse, and 20 A
motor power fuse

Four 0.125” diameter mounting holes
for #4 screws, spaced at 4.60 x 3.35 in
(11.68 x 8.51 cm)

Communication Interface: USB mini-B
connector (enumerates as a serial
COM port)

Operating temperature: 32 to 158 °F
(0 to 70 °C)

Dimensions: 5.05 x 3.80 x 0.97 in
(12.83 x 9.65 x 2.46 cm)
Application Ideas
 Autonomous navigation robots
 Telepresence robots
 Two-wheeled balancing robots
 Robotic arm
 Manufacturing automation equipment
Note: #28993 includes the Eddie Control Board (#550-28990) and the Eddie Control Board Power
Connector (#700-00230). When the Eddie Control Board is purchased as part of the Eddie Robot
Platform kit (#28992) the Power Connector is not required; that kit includes the Eddie Wiring Harness.
Copyright © Parallax Inc.
Eddie Control Board (#550-28990, 28993)
v1.2 2/10/2012 Page 1 of 9
Board Overview
5 VDC
Regulator
Digital I/O
Power Out for
Kinect Camera
10-bit, 8-channel
ADC
Fan Port
(5 V)
Copyright © Parallax Inc.
3.3 VDC
Regulator
12 VDC Regulator
(Kinect Power)
USB Port
Reset
Button
Aux. Power
Fuse (5 A)
Power Input
Port
Regulated Power
Headers
Motor Power
Fuse (20 A)
AUX Switched
Power Ports
Power Enable
Switch
Propeller P8X32A
Microcontroller
Integrated
H-bridges
Extra I/O
Eddie Control Board (#550-28990, 28993)
Left and Right
Motor Plugs
v1.2 2/10/2012 Page 2 of 9
WARNING!

After switching main board power off, wait at least 5 seconds before
switching power back on. Rapid and repetitive power cycling of the
board and motor power supplies causes significant stress on electronic
components and may damage the board and/or connected electronic
accessories.

After prolonged operation, use care when handling the board as some
components may be hot to touch.

This board contains components which are sensitive to static electric
discharge. Ensure proper grounding prior to operating on or around
the board.
Absolute Maximum Ratings
Absolute Maximum Ratings are limits beyond which device damage may occur. Refer to Electrical
Characteristics section (page 4) for operating specifications.
Symbol
Parameter
Value
Units
VCCMAIN
Supply voltage for main board
24
V
TA
Operating temperature
0 to 70
C
TST
Storage Temperature
-55 to 150
C
25
V
20
A
Main Board
H-bridges
VCCMOTORS
IMOTORS(MAX)
Supply voltage for motor H-bridges
Maximum H-bridge output current (surge)
(1)
AUX Switched Power Ports
ID(AUX)
Open-drain MOSFET switch current(2)
5
A
VIH(ADC)
ADC input high voltage
VOUT(5V) + 0.6
V
VIL(ADC)
ADC input low voltage
VOUT(5V) – 0.6
V
I/O pin current (on any I/O pin)
40
mA
Open-drain MOSFET switch current
320
mA
ADC
Digital I/O
II/O(MAX)
Fan Port
ID(FAN)
Notes:
1.
2.
Each H-bridge has over-current and over-temperature protection; however, repeated stress will reduce life. Therefore
the maximum current is limited by the protective 20 A fuse. Maximum current is the combined total for both channels.
Maximum current for AUX switched power ports is limited by protective 5 A fuse. Maximum current is the combined total
for all channels.
Copyright © Parallax Inc.
Eddie Control Board (#550-28990, 28993)
v1.2 2/10/2012 Page 3 of 9
Electrical Characteristics
Unless otherwise noted, all parameters apply at VCCMain = 12V, VCCMotors = 12V, TA = 0C to +70C.
Unless otherwise noted, typical values apply for VCCMain = 12V, VCCMotors = 12V, TA = +25C.
Symbol
Parameter
Conditions
Min
Typ
Max
Units
18
V
Power Input Port
VCCMAIN
Supply voltage for main board
IMAIN(SUPPLY)
6.75
“OFF” state
VCCMAIN = 12V
TA = 25C
“Board” state
VCCMAIN = 12V
TA = 25C
Supply current
345
A
20.6
mA
12 VDC Regulator
VOUT(12V)
Regulated output voltage
11.7
IOUT(12V)
Maximum total output current
2.2
VRIPPLE(12V)
Typical VOUT ripple under load
IOUT = 1.2A
12.0
12.3
V
A
200
mVP-P
5 VDC Regulator
VOUT(5V)
Regulated output voltage
4.85
IOUT(5V)
Maximum total output current
3.0
VRIPPLE(12V)
Typical VOUT ripple under load
IOUT = 500mA
5.0
5.15
V
A
15
mVP-P
3.3 VDC Regulator
VOUT(3.3V)
Regulated output voltage
IOUT(3.3V)
Maximum total output current(1)
H-bridges
3.23
3.3
3.37
TA ≤ 25C
1000
mA
TA = 70C
625
mA
(2)
VCCMOTORS
Supply voltage for motor H-bridges
IMOTORS(SUPPLY)
5.5
“OFF” state
VCCMOTORS =
12V
TA = 25C
“Motors” state
VCCMOTORS =
12V
TA = 25C
Supply Current
16
A
4.5
mA
Motor driver continuous output
current
±10
RONHS
Static high-side resistance
28
RONLS
Static low-side resistance
10
fPWM
PWM frequency
PWM minimum off time
Copyright © Parallax Inc.
0
(3)
Eddie Control Board (#550-28990, 28993)
V
22
IOUT(MOTOR)
tOFF(MIN)
V
A
m
20
kHz
6
s
v1.2 2/10/2012 Page 4 of 9
Symbol
Parameter
AUX Switched Power Ports
VDSS(AUX)
Min
Typ
Drain-source breakdown voltage
Units
V
Continuous drain current
RDS-ON(AUX)
Max
30
(5)
ID(AUX)
ADC
Conditions
(4)
5
Static drain-source on-resistance
22
A
m
(6)
VRANGE
Input voltage range for ADC1-7 pins
LSB
Least significant bit (resolution)
fCLK
ADC clock frequency
3.6
MHz
tCONV
ADC sample conversion time
10
clk cyc.
tSAMPLE
ADC input sample time
1.5
clk cyc.
ADC throughput rate
200
Ksps
fSAMPLE
Digital I/O
0
VOUT(5V)
4.88
V
mV/bit
(7)
RS
Protective series resistance
4.7
k
Fan Port
ID(FAN)
Notes:
1.
2.
3.
4.
5.
6.
7.
Continuous drain current
250
mA
The 3.3 V linear regulator can supply up to 1 A at 25 C. Above 25 C, maximum current is de-rated according to
ambient temperature (TA) based on the following equation: IOUT(3.3V) = (150 C – TA)/(75 C/W * 1.7 V).
For further details and specifications for the H-bridge drivers, please refer to the component datasheet for the
STMicroelectronics VNH2SP30-E.
To avoid false Short to Battery detection during PWM operation, the PWM signal must be low for a time longer than 6 s.
For further details and specifications for the low-side AUX power MOSFET switches, please refer to the component
datasheet for the Diodes Inc. DMG4496SSS.
Maximum MOSFET open-drain output current is limited by protective 5 A fuse.
For further details and specifications for the ADC, please refer to the component datasheet for the Microchip MCP3008.
For further details and specifications for the Propeller microcontroller and its I/O pin capabilities please see the P8X32A
component datasheet.
Operating Description
Power Input Port
Main board power and motor power are supplied to the board through a high-current 3-pin header. The
header is part of the Molex Mini-Fit Sr. series of connectors. The pin functions are shown below.
Pin
Function
GND
Common ground for main board power and motor power
Main
Input supply for main board circuitry, power supplies, and AUX switched power ports.
Motors
Power supply for H-bridge drivers only. Power to this pin is routed through the 20 A fuse.
The isolation of the Motor power supply from the rest of the board and Main circuitry allows the motors
to be fully disabled without affecting operation or power to any other part of the board.
Copyright © Parallax Inc.
Eddie Control Board (#550-28990, 28993)
v1.2 2/10/2012 Page 5 of 9
12 VDC Regulator
The integrated 12 VDC buck-boost switching regulator provides a consistent stable output voltage across
the entire operating input voltage range. For high values of VCCMAIN the regulator operates entirely in
buck mode, but as input voltage decreases the regulator gradually transitions into a buck-boost mode to
seamlessly maintain the output voltage at 12 V.
The 12 VDC regulator circuit is designed to supply power to a Microsoft Kinect camera through the boardmounted Molex Micro-Fit 3.0 header. Supplied with each Eddie Robot Platform (28990 and 28992), the
modified Kinect adapter cable uses the corresponding mating connector to allow easy assembly.
The Kinect camera requires a 12 V power supply rated up to 1.08 A capacity. The on-board 12 VDC
regulator circuitry was intentionally designed to supply up to 2.2 A total output current to accommodate
any extra user-added circuitry requiring regulated 12 V. The regulated power header marked “12V”
provides convenient access to this 12 VDC regulated supply. Users may draw up to the full rated 2.2 A
from this header; however when a Kinect camera is attached, no more than 1.12 A should be drawn from
this header to remain below stated limits and ensure proper operation.
5 VDC Regulator
The integrated 5 VDC buck switching regulator provides up to 3 A total current to several on-board
circuits as well as any attached 5 V sensors and accessories. The 5 VDC regulator also supplies power to
the 3.3 V linear regulator. The center column of pins on the Digital I/O headers and ADC headers are
connected directly to this 5 VDC regulated supply. The regulated power header marked “5 V” also
provides convenient access to this power supply.
3.3 VDC Regulator
The 3.3 VDC linear regulator provides clean supply voltage to the Propeller microcontroller and other
associated 3.3 V circuitry. Note: under certain conditions instantaneous high-current step transients may
cause ringing in the output voltage.
At TA = 25C, the regulator can supply up to 1 A total output current, but at higher temperature the
maximum current must be de-rated according to ambient temperature (TA) based on the following
equation:
150
.
75

1.7
Regulated Power Headers
For convenience, 2-pin female headers are installed to provide access to each regulated supply net.
Power may be drawn from these headers to power additional user-circuitry as long as the total output
current for each regulator does not exceed the specified ratings.
Copyright © Parallax Inc.
Eddie Control Board (#550-28990, 28993)
v1.2 2/10/2012 Page 6 of 9
Power Enable Switch
The power enable switch controls the operating mode of the regulators and H-bridges according to the
state table shown below.
Position
State of Operation
12 VDC and 5 VDC Regulators
H-bridge Drivers
STBY/OFF *
Disabled
Disabled
Board
Enabled
Disabled
Motors
Enabled
Enabled
(1)
Notes:
1.
Rev A boards show silkscreen text as “OFF”, while Rev B and later boards show silkscreen text as “STBY”. The circuits
relating to this feature were not changed.
In the “STBY/OFF” state, the switch does not actually break the electrical connection to the entire board.
All the circuits are disabled but battery power is still present and a very small amount of current is drawn
(typically around 345 A). The Eddie Robot Platform comes with large capacity sealed lead-acid batteries
totaling 14.4 Ah, so this small current draw is insignificant. In fact, the batteries’ own self-discharge rate
is several times larger than the standby current of the Eddie Control Board. Additionally, sealed lead-acid
batteries should be recharged at least every few months to maintain proper battery health regardless of
whether the batteries were used or not.
In applications where battery capacity is in question, external high-current (25 A minimum
recommended) power switches should be wired in series with the “Main” and/or “Motors” terminals on
the power input port connector.
H-bridges
The board is equipped with two high-current integrated full H-bridge drivers. While each H-bridge IC is
technically rated up to a maximum of 30 A output current (according to the device datasheet), design
trade-offs and thermal limitations require each driver be de-rated to 10 A continuous per channel. This is
more than adequate for the motors included in the Eddie Robot Platform as well as motors typically used
in most small to mid-sized robotics applications.
The “Motors” terminal on the power input port is connected to the supply voltage of each H-bridge
through a 20 A mini-blade automotive fuse. For safety and circuit reliability, this fuse should only be
replaced with an equivalent 20 A fast-blow mini-blade fuse.
AUX Switched Power Ports
The auxiliary (AUX) switched power ports provide unregulated power from the “Main” terminal on the
power input port through a 5 A mini-blade automotive fuse to the ‘+’ side (on the right) of each screw
terminal. A power MOSFET switch then selectively switches the low side of the terminal (on the left) to
ground, turning on whatever accessory is connected to the port. The MOSFET gates for switches A, B,
and C are connected to Propeller pins P16, P17, and P18 respectively. These AUX switched power ports
are very useful for powering LED light strips, auxiliary motors, and other electronic accessories and allows
for these devices to be controlled in software.
Copyright © Parallax Inc.
Eddie Control Board (#550-28990, 28993)
v1.2 2/10/2012 Page 7 of 9
Propeller Microcontroller
The Propeller P8X32A contains eight 32-bit microcontroller cores each operating at up to 80 MHz. An onboard 512 K-bit EEPROM provides storage for program memory as well as ample storage for additional
non-volatile data. Application firmware can be loaded into RAM or automatically loaded from the external
EEPROM on power-up.
In some applications it may be useful to lock the firmware into EEPROM so it cannot be overwritten either
intentionally or unintentionally. For this purpose, through-hole pads were provided as an option to install
a header or jumper wire to disable EEPROM write capability. By default, the pads are left unpopulated so
reading, writing, and programming are fully enabled. When a jumper is installed to short the two pads
together, then EEPROM programming/writing is disabled but reading will still be enabled.
A 5 MHz crystal oscillator and reset button complete the onboard Propeller circuitry.
Digital I/O and Extra I/O
Most of the Propeller’s 32 general purpose I/O pins are used to interface with on-board peripherals, or
connect to headers for sensor interfacing. While there are already 12 general purpose digital I/O pins
brought out (including the Encoders section), each of these pins has a 4.7 k series resistor for
protection. This allows direct 3.3 V or 5 V sensor interfacing while preventing damage to the Propeller.
However in situations where direct connection to Propeller I/O pins is necessary (or using a resistance
other than 4.7 k), four “Extra I/O” pins have been brought out to pads through 0  resistors. If
necessary, the 0  resistors can be replaced with any other desired value.
The Digital I/O pins are brought out to twelve 3-pin headers near the edge of the board. The order of
the pins from left to right is: Ground, 5 V, Signal. Some rules of thumb to remember this order is to
keep the signal wire (typically colored white) close to the white silkscreen line located toward the center
of the board (to the right of the header). Additionally, having the signal wires oriented toward the center
of the board results in the shortest signal path back to the Propeller I/O pins.
ADC
For the analog to digital converter, the board is equipped with the Microchip MCP3008 which is an
8-channel, 10-bit ADC. For further device details about this ADC, please refer to the manufacturer’s
datasheet.
On this board, only seven of the eight ADC channels are brought out to 3-pin headers. The eighth
channel is connected through a voltage divider to VCCMAIN, the main supply voltage to the board. This
allows convenient measurement and monitoring of the battery voltage level by application code.
Fan Port
During typical operation, the power dissipated by all the circuits will be minimal and a cooling fan is not
necessary. However, when power dissipation becomes an issue due to continuously high motor output
current or current draw from the regulators near the stated maximum limits, a cooling fan can be used to
improve and extend circuit operation.
The fan port is populated with a 0  resistor to the 5 VDC net (located near the fan port just below the
ADC). Many 12 V fans still operate well at 5 V and are typically much quieter. If desired, the 0  resistor
can be de-soldered and repositioned directly below its current location to instead route VCCMAIN to the fan
port. Note that in this configuration, the low-side MOSFET switch will still turn off when the power
enable switch is in the “STBY/OFF” state.
Copyright © Parallax Inc.
Eddie Control Board (#550-28990, 28993)
v1.2 2/10/2012 Page 8 of 9
Additional Resources and Information
For additional information and resources go to www.parallax.com/eddie.
Revision History
Version 1.0

Initial product documentation release.
Version 1.1

In Power Enable Switch section (page 7), updated table and notes to mention silkscreen
differences from Rev A to Rev B and later boards.

Added further explanation in the Fan Port section (page 8) about voltage configurability option.
Version 1.2

Updated images for Rev B of the board. Note added to the bottom of page 1.
Copyright © Parallax Inc.
Eddie Control Board (#550-28990, 28993)
v1.2 2/10/2012 Page 9 of 9