Review Request for my robot(so far)

[pkshima]

Could you please take a look at the schematic of my robot so far and see if I have missed something or went wrong somewhere. I am a software guy so please be nice

P.S: The open ended resistors go to the motor controller which works well.

 

[Pommie]

It looks fine except for sharing the ICD pins with the motor drive. Doing it this way you will not be able to debug. Why don't you use port A to drive your motor.

Mike.

 

[pkshima]

Thats a nice point. I think I will do that now. I chose the present pins just beacuse of their positions. I thought it would be easier to fabricate it on a veroboard.

 

[pkshima]

Oh just a sec. Its a pic16F628A so if I am right I wont be able to debug anyways. So I think the current pin usage will work fine ?

 

[Pommie]

Whoops, you are correct. I am so used to using the 16F88 that I forgot that small point. Maybe you should consider the 88 as having debug facilities is so useful.

Mike.

 

[blueroomelectronics]

The MCLR diode is backwards.

 

[pkshima]

gee I am such a ... noob.
Thanks.

Pommie, I also wanted to go with the 88 but it was just not available here. I am planning to move to C on 18 series altogether but still using 16F for the time being just to be able to teach myself how to keep the costs low and how to code in assembly.

 

[pkshima]

BTW, I read in many places that the mclr diode is optional. I dont understad why. If I dont put it, I might fry the TSOP1738 ! or am I missing something.

 

[blueroomelectronics]

The diode is optional, what it does is prevent the VPP from putting current on the VDD line.
The TSOP1738 needs a 100ohm and 4.7uF cap on it for proper operation.

 

[pkshima]

I see. Does it mean that even if there is no diode to prevent VPP from putting current on the VDD line, the TSOP will be fine all thanks to the 100ohm and 4.7uF ?

 

[blueroomelectronics]

VPP should be very low current, it can't hurt your TSOP1138.