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Microcontroller

    The following chart compares some basic features of some of the microcontrollers used in the club.   Links to more data on some of the controllers are given after the chart.

 

Basic Stamp
BS2-IC

BX24

PIC
16F877

68HC912B32
TechArts module

68HC11E1
Tcomp 4.5 board

Clock Speed

20 MHz
4K LOC/sec

? MHz
65K LOC/sec

20 MHz

8 MHz

8 MHz

EEPROM/Flash

2K
500 LOC

32K
8000 LOC

8K

32K

1/2K

RAM

32

400

368

1024

32K

Memory Expansion?

no

no

 

64K RAM

64K

Digital I/O

16 general purpose I/O

16 (less those used for analog)

33 (less those used below?)

63 (less those used below)

21 (less those used below)

Source/Sink current

20/25 ma

10/20 ma

25/25 ma

25/25 ma

?/25 ma

Analog input

For resistive sensors 16bit

8 chan

8 chan 10 bit

8 chan 8 bit

8 chan 8 bit

Inp/Out capt

Input cap

 

yes

8: inpt cap or out comp

4 inpt cap
5 output comp

Pulse accum

Yes

 

no

Yes

Yes

PWM channels

Yes

2

2

4 8bit/2 16bit

4 16 bit

Serial interface

RS232 (up to 16)

RS232/SPI or parallel

RS232? External components?

RS232/SPI

RS232/SPI

Real Time Intr

no

Yes??

Yes

Yes

Yes

Other interrupts

no

 

14,
3 timers:
1x16bit
2x 8bit
1 WDT(COP)

2 external
8 timer chans
ATD
2 pulse accum
COP

2 external
8 timer chans
2 pulse accum
COP

Power req’mt

5vdc or >8
7 ma.

4.8 to 15 vdc
20 ma.

5 vdc +/- 10%
2 ma.

5 vdc or > 8
25 ma.

5 vdc
?

Programming

Built-in Pbasic interpretor.

 

Assembler
Basic
C

Freeware:
Assembler
Sbasic
Gnu C
Costware:
Imagecraft C
Etc.

Freeware:
Assembler
Sbasic
Tiny4th
MaxForth
Costware:
Interactive C
Imagecraft C

Floating point math?

No

Yes

Yes

Yes..with Imagecraft C

Yes, with Max-Forth & Img C

Other features

 

Trig,log,exp,sqrt functions.

Networks

Multitasking

RS485
Supports
Multidrop
I^2C

Card inserts into standard protoboard
RS485

Board has 2 H bridge drivers for robot wheels

Price

$50.

$100 starter kit

$50 chip

$12. 
Build programmer for $6

$120 starter kit
$99 module
$49 64k RAM

$135

More data:

Basic Stamp 2:  Manufacturer site is Parallax.com.  Skip down to the BS2-IC part number  and go back to their home page to find more info.

                            Jim Ubersetzig has sample software to perform many functions on the BS2, (including driving an Ebot).  This alone is a good reason to go with the Basic Stamp.  Click here for a list of software that he has available.  A program to run Ebot can be found on the programming page.

                            Jim also supplied a schematic of how to hook up a BS2 to drive your robot.  ALL the wiring required is given.

                            One disadvantage to the Basic Stamp is that it does not have interrupts.  When we get to installing encoders on the wheels to measure distance traveled, the Stamp will have to read the encoders by polling very frequently to determine when the encoder pulses appear.  This makes it difficult to get any other processing done.  However, there is a simple hardware circuit available which can be added to eliminate this problem.  The circuit is provided later.

PIC:       Manufacturer data is available from www.microchips.com

       Support equipment including an In-Circuit programmer and PBasic compiler can be seen at   microengineeringlabs.com/products/pbp.htm

68HC912B32:  Click here for a description of the Adapt912 implementation of the 68HC912B32 by Technological arts.