# PIC 8-bit rapid prototype development boards...?

F

#### frenchy

Jan 1, 1970
0
Howdy all,
I recently took a class from Microchip learning to use their PIC24F 16-
bit micros. I got the Explorer 16 development board and the ICD2 LE
and got everything up and running with their MPLAB IDE v8.02 yadda,
yadda. Everything is going very well, but I dont have any prior
experience using more lowly 8-bit micros.

A friend of mine wants me to design and build a little controller unit
to put inside of his remote control boat that will receive some of the
servo signals from a couple of different receiver channels and be able
to fire some rockets and trigger various aquatic peripherals. This
seems to me like I should look to an 8 or 14 pin 8-bit solution and
that a 100-pin 16-bit processor would be significant overkill
(understatement).

I looked at the receiver servo signals on a scope and they are strange
PWM type signals that vary in pulse width depending on what the
transmitter/controller is doing (not sure if I should average them to
DC and look at the DC level using an ADC or not). Anyway, it is my
job to receive the various servo signals from the receiver and write a
little program to have the micro control a couple of outputs to:

a) light a fuse on a bottlerocket
b) send out pulses to trigger a paintball firing mechanism (fully-
automatic or semi-automatic or one-shot).
c) perhaps a few other tricks.

My question is this....
1) Will my new ICD2 LE work with lowly 8-pin and 14-pin PIC 8-bit
micros in addition to the PIC24F 16-bit micros?
2) Although I have designed and build hundreds of my own PCBs in the
past, this project doesnt really warrant a custom designed and built
PCB...instead I would like to buy an "off the shelf" development board
that will allow an 8-pin or 14-pin micro to be used to accept a couple
of receiver servo pulse width inputs and actuate a couple of output
transistor/driver circuits for US$20-40ish. Sure I could design my own PCB, but I would like to keep my actual design time limited to a couple of hours tinkering with the code instead of spinning a PCB, specing and ordering parts, etc. Any suggestions on quick deployment general purpose PIC development kits for such an application? I found this... http://www.talkingelectronics.com/projects/PIC_Lick-1/PicLick-1-P1.html It looks like the best so far for$30 or so with the PCB and all
parts.

I also saw this, but would require more tinkering for the output
stages...
http://www.microchipdirect.com/productsearch.aspx?Keywords=soic8ev
http://www.microchipdirect.com/productsearch.aspx?Keywords=soic14ev

Thx for any input.
respectfully,
frenchy

D

#### donald

Jan 1, 1970
0
frenchy said:
Howdy all,
I recently took a class from Microchip learning to use their PIC24F 16-
bit micros. I got the Explorer 16 development board and the ICD2 LE
and got everything up and running with their MPLAB IDE v8.02 yadda,
yadda. Everything is going very well, but I dont have any prior
experience using more lowly 8-bit micros.

Welcome to the world of mocrocontrollers.
A friend of mine wants me to design and build a little controller unit
to put inside of his remote control boat that will receive some of the
servo signals from a couple of different receiver channels and be able
to fire some rockets and trigger various aquatic peripherals. This
seems to me like I should look to an 8 or 14 pin 8-bit solution and
that a 100-pin 16-bit processor would be significant overkill
(understatement).

Good idea.

I looked at the receiver servo signals on a scope and they are strange
PWM type signals that vary in pulse width depending on what the
transmitter/controller is doing (not sure if I should average them to
DC and look at the DC level using an ADC or not). Anyway, it is my
job to receive the various servo signals from the receiver and write a
little program to have the micro control a couple of outputs to:

a) light a fuse on a bottlerocket
b) send out pulses to trigger a paintball firing mechanism (fully-
automatic or semi-automatic or one-shot).
c) perhaps a few other tricks.

This may help:
http://www.seattlerobotics.org/guide/servos.html

There are many solutions to this problem.

The micro counting the pulse width of at least two servos pulses,
at the maximum of both pulses can trigger an output to trigger the "gun"
My question is this....
1) Will my new ICD2 LE work with lowly 8-pin and 14-pin PIC 8-bit
micros in addition to the PIC24F 16-bit micros?
Yes

2) Although I have designed and build hundreds of my own PCBs in the
past, this project doesnt really warrant a custom designed and built
PCB...instead I would like to buy an "off the shelf" development board
that will allow an 8-pin or 14-pin micro to be used to accept a couple
of receiver servo pulse width inputs and actuate a couple of output
transistor/driver circuits for US$20-40ish. Any vector plug board and point to point soldering. Sure I could design my own PCB, but I would like to keep my actual design time limited to a couple of hours tinkering with the code instead of spinning a PCB, specing and ordering parts, etc. Any suggestions on quick deployment general purpose PIC development kits for such an application? I found this... http://www.talkingelectronics.com/projects/PIC_Lick-1/PicLick-1-P1.html It looks like the best so far for$30 or so with the PCB and all
parts.

I also saw this, but would require more tinkering for the output
stages...
http://www.microchipdirect.com/productsearch.aspx?Keywords=soic8ev
http://www.microchipdirect.com/productsearch.aspx?Keywords=soic14ev

Thx for any input.
respectfully,
frenchy

Good luck

Please post some pics on your favorite pics site, or utube a video.

donald

S

#### Spehro Pefhany

Jan 1, 1970
0
Howdy all,
I recently took a class from Microchip learning to use their PIC24F 16-
bit micros. I got the Explorer 16 development board and the ICD2 LE
and got everything up and running with their MPLAB IDE v8.02 yadda,
yadda. Everything is going very well, but I dont have any prior
experience using more lowly 8-bit micros.

A friend of mine wants me to design and build a little controller unit
to put inside of his remote control boat that will receive some of the
servo signals from a couple of different receiver channels and be able
to fire some rockets and trigger various aquatic peripherals. This
seems to me like I should look to an 8 or 14 pin 8-bit solution and
that a 100-pin 16-bit processor would be significant overkill
(understatement).

I looked at the receiver servo signals on a scope and they are strange
PWM type signals that vary in pulse width depending on what the
transmitter/controller is doing (not sure if I should average them to
DC and look at the DC level using an ADC or not).

You should measure the pulse width, which should be between 1000 and
2000 usec, roughly.
Anyway, it is my
job to receive the various servo signals from the receiver and write a
little program to have the micro control a couple of outputs to:

a) light a fuse on a bottlerocket
b) send out pulses to trigger a paintball firing mechanism (fully-
automatic or semi-automatic or one-shot).
c) perhaps a few other tricks.

My question is this....
1) Will my new ICD2 LE work with lowly 8-pin and 14-pin PIC 8-bit
micros in addition to the PIC24F 16-bit micros?

Yes, although you should probably stick with ones that allow you to
dedicate the programming pins, so 16 or 18 pins might be more
appropriate.
2) Although I have designed and build hundreds of my own PCBs in the
past, this project doesnt really warrant a custom designed and built
PCB...instead I would like to buy an "off the shelf" development board
that will allow an 8-pin or 14-pin micro to be used to accept a couple
of receiver servo pulse width inputs and actuate a couple of output
transistor/driver circuits for US$20-40ish. Sure I could design my own PCB, but I would like to keep my actual design time limited to a couple of hours tinkering with the code instead of spinning a PCB, specing and ordering parts, etc. Any suggestions on quick deployment general purpose PIC development kits for such an application? I found this... http://www.talkingelectronics.com/projects/PIC_Lick-1/PicLick-1-P1.html It looks like the best so far for$30 or so with the PCB and all
parts.

I also saw this, but would require more tinkering for the output
stages...
http://www.microchipdirect.com/productsearch.aspx?Keywords=soic8ev
http://www.microchipdirect.com/productsearch.aspx?Keywords=soic14ev

Thx for any input.
respectfully,
frenchy
Best regards,
Spehro Pefhany

N

#### nospam

Jan 1, 1970
0
frenchy said:
My question is this....
1) Will my new ICD2 LE work with lowly 8-pin and 14-pin PIC 8-bit
micros in addition to the PIC24F 16-bit micros?

The ICD2 should program any PIC supporting ICSP. Many low end PICs don't
have in circuit debug, or only have it special packages with extra pins

You would need to use a Microchip AC162053 adapter (about $35) to get ICD on a 16F628A design for example. If you want to write in C the device support offered by the limited free compilers bundled with MPLAB would also be a consideration. For a one/few off the cost difference between a low end PIC24 and a PIC16 is trivial, you can get small ones in 28 pin DIL. -- F #### frenchy Jan 1, 1970 0 Donald wrote: > This may help:http://www.seattlerobotics.org/guide/ servos.html Frenchy responds: This did help, thank you!! We are using a Futaba set-up that looks very similar to that shown in the picture. Transmitter = Futaba FG series Receiver = FP-R7H Donald wrote: > The micro counting the pulse width of at least two servos pulses, at the maximum of both pulses can trigger an output to trigger the "gun" Frenchy responds: When picking the micro (my first 8-bit project), if I want to count the pulse width of three servo intputs (for 3 different output functions), does that mean that I need three separate 8-bit timers? I am going to research the "counting width" method now. Thank you. thx, frenchy D #### donald Jan 1, 1970 0 frenchy said: Donald wrote: > This may help:http://www.seattlerobotics.org/guide/ servos.html Frenchy responds: This did help, thank you!! We are using a Futaba set-up that looks very similar to that shown in the picture. Transmitter = Futaba FG series Receiver = FP-R7H Donald wrote: > The micro counting the pulse width of at least two servos pulses, Frenchy responds: When picking the micro (my first 8-bit project), if I want to count the pulse width of three servo intputs (for 3 different output functions), does that mean that I need three separate 8-bit timers? I am going to research the "counting width" method now. Thank you. thx, frenchy As I stated earlier, there are many ways to do this. One way: Set an interrupt to trigger on 100 uSec interrupts. At each interrupt test the three bits and count a variable up if the bit is high, zero that variable if the bit is low. Outside the interrupt, test the three variables for a maximum value: 2mSec / 100uSec = 20. Anything above say 18 is maximum. So two variables above 18 will set another variable, and trigger the "gun". On the remote control, pushing two axis to the maximum for only an instant, will trigger the "gun". Good luck donald F #### frenchy Jan 1, 1970 0 The ICD2 should program any PIC supporting ICSP. Many low end PICs don't have in circuit debug, or only have it special packages with extra pins used on ICD adapters. You would need to use a Microchip AC162053 adapter (about$35) to get ICD
on a 16F628A design for example.

Aha, I thought those adapters were just to interface with that stupid
proprietary phone jack....but now I see that they are for use with
devices that dont have debug functionality built-in....very strange.

If you want to write in C the device support offered by the limited free
compilers bundled with MPLAB would also be a consideration.

For a one/few off the cost difference between a low end PIC24 and a PIC16
is trivial, you can get small ones in 28 pin DIL.
--

Great advice! I guess since I already have the C30 compiler set-up
and working, I should just get the lowest pin-count PIC24F that is
supported by my compiler. I didnt realize they went down to 28-pin in
a dip package. Nice. I just noticed, however, that they are all 2.0
to 3.6vdc devices. I already have a 5vdc regulator in the system that
I was going to tap onto for power. I guess I can add another 3.3v
regulator running off from the existing 5v regulator (not too much
wasted power to drain the batteries). The input Servo pulses coming
from the Futaba receiver dont matter if they go above the 3.3v rail as
long as I have 10k series resistors in-line to limit the injection
current. Also, the output NPN transistors dont care if their bases
are driven by 3.3v as long as the emitters are tied to GND and I have
resistors in the base right?

thx,
frenchy

F

#### frenchy

Jan 1, 1970
0
As I stated earlier, there are many ways to do this.

One way:

Set an interrupt to trigger on 100 uSec interrupts.
At each interrupt test the three bits and count a variable up if the bit
is high, zero that variable if the bit is low.

Outside the interrupt, test the three variables for a maximum value:
2mSec / 100uSec = 20.

Anything above say 18 is maximum. So two variables above 18 will set
another variable, and trigger the "gun".

On the remote control, pushing two axis to the maximum for only an
instant, will trigger the "gun".

Good luck

donald

Donald,
Thanks again for answering my elementary questions. Is there any
advantage to using the input capture peripheral (Five 16-Bit Capture
Inputs) when counting the length of these servo inputs?
thx,
frenchy

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