Ladybug new design 18F2525 PLC first looks.

[William At MyBlueRoom]

Here's the layout (sorry it's lores here, I'll post a full size on my site asap)

I want to remove the crystal on the 18F2525 *you can calibrate it with the DS1306 32KHz
I even considered using a 7.3728MHz oscillator and the /4 to drive the MAX3110E at 1.8MHz but I'd rather use less crystals than more... SO What shall I do with the 2 I/O pins RA6 & RA7?
This Firefly can work standalone as a PLC or a good way to test your C skills as the 18F is better suited for C than a 16F PIC.

The PCB will be another 107x57mm for fitting in a Hammond enclosure.
**broken link removed**

 

[mramos1]

Maybe IR to control the relays from a standard TV remote as well as the RS232? Or a couple bottons/switched to override what it is controlling locally?

 

[William At MyBlueRoom]

It's designed to be remote, rarely near an IR. It did occur to me to remove the DS1306 and use a cheaper I2C DS1307 on RA6,7. It would be a software I2C but in the long run probably eaiser to use if you're not switching the MAX3110E. It still frees up a pin lol.
Also an I2C I could throw a 24C256 at it.
Hmmm.... Now just one I/O pin.

Watch the schematic change...

 

[mramos1]

I know it is a remote unit. My thought was to control it if you were near it. I thought IR in a home or just botton(s) to control it in a commercial environment. You can do a lot with 2 pins.

I like the 24C256 idea too. Logs are good.

 

[William At MyBlueRoom]

Ok I'll add the IR as an option on that RB5 pin, refresh to see a new schematic.

 

[mramos1]

IR or two monentary switched to change it. IR was because I am just lazy.

Will check it out. After shopping will start playing with the firefly.

Start up a small shell program for simple projects. Not sure it I will do ASM yet or Mikrobasic. I will see what you and Pommie have posted and deceide from there.