Win a HitBoard!! - ATMega1281 based Robot Control Board
The power of H8
16(XVI) bits
XVI Board is a Robot Control Board. It contains a H8/3664 (16bit) microcontroller, Two High Power H-Bridges (5A DC capacity) and an IR modulator
Downloads: Circuit Schematic 
,
Demo
Source Code,
and Quick Start
Manual
XVI-Board CONTEST OVER
UPDATE:
This contest is OVER. The winner was Mr. Chetan Tonde from Pune.
Please see the current
contest for ATMega1281 board (click here).
This page is here for informational
/ documentation purposes only.
Contest Start: June 30, 2006
Contest Ends: July 28, 2006
Board Reaches the Winner: August end, 2006
Contest Open to Indian robot hobbyists only.
Win! XVI Board Contest
The winner of this contest shall receive an XVI Board (H8 Microcontroller Based Robot Control Board), and a CD containing GNU GCC based free software development tools for H8. This page describes the background of this contest, and the Technical specifications of the XVI Board
So What is This About?
Many budding Robotics hobbyists need a good electronic control board to control their robot. The "XVI board" is such a board, with an H8 Microcontroller. All you need to do is start writing your robot control software in C. Before that, however, you need to know the capabilities of the XVI board, and also be aware of the Software Tools you shall use to program the XVI board. This page gives all the details you would need to know and do to use XVI board.
It must be noted that the XVI board might not be suitable for "absolute" beginners. Prior knowledge of any Microcontroller Programming would be necessary, because the H8 Microcontroller is quite powerful. So it may require a little more effort than usual to tap its full potential (when compared to the usual 8-bit microcontrollers: PIC, 8051 etc.). So if you know any other microcontroller programming, i think, it would be an easy and joyful experience to try this 16bit H8 Microcontroller!
XVI Board Features and Summary
Block Diagram:
Fig. 1
XVI Board Specs:
Component
Features
Details
MCU
H8/3664
Maker
Renesas
, (formerly Hitachi), Part No. HD64F3664BP
Core
16Bit , 16 MHz
Memory
Flash: 32KB, RAM: 2KB
ADC
10 Bit, 4channels. Speed:
227.3Ksps. Scan Mode, 4different Registers for auto-scanning
Timers
& PWM
3 Timers: Timer A - Internal
time/base for RTOS or timing only Timer V - 8bit timer, Timer W - 16Bit
5PWM outputs are possible. 2 PWM o/p used for DC motor Driver ICs. 3
PWM outputs available for general use
Serial
Asynchronous UART- Rx/Tx :
Converted to
RS232 level by MAX232 for link to PC serial port. Flash Programming
requires only 3 wire Serial connection to PC.
IIC or (I2C): pins SCL, SDA.
(Note1)
SCI: Pins Rx, Tx, SCK3 (Note2)
H-Bridge
L9929 (2 Motor Drive ICs)
Voltage
Rating
4.5V to 28V
Motor
Current
5A DC Max WITH HEATSINK. (Please
read below about how you would have to make the heatsink yourself)
Protection
Over Current (short to VB
& GND), Short between Terminals, Over Temperature Shutoff
38KHz
Modulated Output
This circuit
generates a 38KHz
carrier signal, which is switched (on/off modulated) by the CPU port
pin P56(SDA). This signal can be used to drive an IR Led transmitter to
be used as an IR obstacle sensor. The IR receiver could be TSOP1738 or
similar. Thus this signal is optimized for TSOP1738 IR receiver. See
below for an example circuit of IR Transmitter.
Debug LED
An LED driven by CPU port P80 for
debugging etc.
Run/Program Switch (S1)
Sets the Microcontroller in Flash
Program Mode
or Run Mode. A reset after each mode change is required. A Reset Push
Button is provided for that.
Size
50mm x 75mm
Participation
This Contest is Over.
Click here for the Online form, and quiz: XVI
Board Contest Application (but please do read below
completely before application)
Frequently Asked Questions (FAQ)
If I dont win this contest, can I buy this board from you /somewhere?
No. I have made only 2 boards. One is for my back-up.
Can i make this board myself ? Would you provide me with the PCB layouts ?
Of-course! You can download the schematic from the links in this page,
and ask me for the PCB layout.
BUT, i think it would be Very Hard to find these ICs in local market in
India. H8 is not so popular. Maybe you could find!
I think the approximate cost of the MCU, would be Rs 500, and H-Bridge
about Rs 900 each. (Thats what I saw for a similar spec. DMOSFET based
H-Bridge IC on some Indian online webshop.)
I have not heard about the H8 Microcontroller. Why did you choose that ?
Two Reasons: First, I had 2 chips free. second : to best of my knowledge, this is most popular Family of microcontrollers for Robotics in Japan. But I dont know how easily we could get Renesas Microncontroller's in India. I had tough time finding them. Moreover, as already mentioned this MCU does have some unique features which are not common in other common hobby MCUs. For example: the ADC has 4 seperate registers for ADC results. This is shown in fig. 3 below.
Fig. 2
Thus the ADC results of 4 channels are stored seperately, automatically, and the Software can read them whenevr it wants. However, every Microcontroller has its pros and cons. The H8 family MCU is also used in the popular Lego Robotics Kit.
Requirements
Things you need to Do before you could use XVI Board (after you get it)
- RS232 Connector: A cable should be made
with a 3 pin connector on one end, and a 9 pin D-sub (f-type) connector
at the other end. This shall be used to connect the CPU to the PC for
flash writing, and debugging the code later.
I shall send the 3 pin connector and the crimps. You would have to attach the crimps to wires and push them in the connector to form the connector. Also, please buy the 9 pin D-sub connector for PC Serial port from local market.
Connections -
XVI board pin ---(about 2m wire)--- 9pin D-sub pin
1 (Tx) ------- 2 (Rx)
2(Rx) ------- 3 (Tx)
3(Gnd) ------- 5 (Gnd)
- Capacitor C2: The voltage rating of Capacitor depends on your motor voltage. It should be twice or higher. So please buy C2, 1000uF, 25V if your power supply is less than 12V. C2 is necessary for good start-up performance of the motors. Please solder C2 yourself. (top side soldering with thin soldering bit is required, underside pads of the board are covered by connector)
- Wire Lugs: It is recommended that you have "Y" shaped lugs crimped on the battery and motor wires so that the copper strands dont break with use, and eventualy damage the board with shorts. Please use thick enough wires to carry your motor current.
(Y
shaped lugs like this are recommended for neat connection to XVI Board)- Heat Sink: If the motor current is
higher than 1A, please
do not use the board without adding a heat sink under the H-Bridges.
There is 1 screwhole near each H-Bridge IC for the heatsink (as shown
below). But there is no ready-made
heatsink available for this design. You will have to make one yourself
with aluminum channel or bars.
It has to be screwed to position Under each H-bridge, where there is
rectangular exposed copper on PCB for good heat conduction. However, a
thin mica sheet is also required for insulation because there is also a
exposed copper track (highlighted by red in photo below). If used
without the Heat-sink at high current,
the H-Bridges WILL BE DAMAGED.
Fig. 3: Bottom side of XVI Board.
Some Tips for using the XVI Board
- DC Motors and PWM Speed Control Although
the Demo Program
source shall eventually explain how the speed and direction of the DC
motors is controlled in XVI board, here is the basic concept.
Each H-bridge IC gets 1 PWM and 1 direction bit input from the MCU. When the direction of the motor is to be reversed, the Direction bit set to High, And the PWM is set to Active "low" duty. Figure below shows the Motor1 being run at "same speed" in opposite directions, because the PWM active duty is the same.
Fig. 4
- IR Led Modulator An example circuit for
IR led transmitter which could be connected to the OSC output of the
XVI board is shown below.
Fig. 5
The IR led carrier freq is set to 38KHz. but it may vary by about 1KHz due to variations in R, C. So if you find that your IR receiver does not have a good range, please try to tune circuit by changing R6 a little (by few hundred ohms). Note that its a SMD part. 0603 size. Other way to get a precise 38KHz is to use one of the timer-output ports of the MCU.
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Copyright: Vivek Vaid
Last updated: 2006, June 24