PIC DEV BOARD

[m.kaviani]

dear dude
I am developing my own industrial Pic development board based on 18F66k80 64MHz 8bit advanced PIC micro.
my board contains:
1- ad7705 16bit 2ch a/d
2- ds1307 rtc
3- i2c eeprom 24c02
3- x1 to x500 instrument amplifier with 0..2.5v offset
4- 4-20mA input
5- 4-20mA output
6- modbus
7- canbus
8- rs232 port
9- mini USB with ch340e USB to ttl
10- +15 volt to 5 volt with lm2675
11- 12v step-up converter for opamp
12- esp8266-12e wifi
13- 12bits dac
14- i2c oled display
15- 2*16 or 4*20 lcd connector
16- 3 free button
17- 3 free led
18- 3.3v
19- -5v
20- buzzer
21- free pot trimmer for analog input
22- 0-100 volt dc input
23- spi/i2c connector
24- TTL serial connector
25- 12 test point
26- spi sd card reader
27- pik3 connector
28- esp8266 serial connector

I will gladly so if you have new suggestion to improve the board.   

[TimB]

That will be a beast of a board.

But connecting your own test boards looks difficult.

Tim

[m.kaviani]

That will be a beast of a board.

But connecting your own test boards looks difficult.

Tim

we are on vacation in Iran. and I have enough time to change and compress the board.

[ken_k]

Hi the board looks very good, I like the canbus and modbus, did you consider using a 16 bit device?

[m.kaviani]

Hi the board looks very good, I like the canbus and modbus, did you consider using a 16 bit device?

The reason is price . So many industrial project will handle with a simple 16f or 18f device. 16bit device are so power and fast.
But price in design is important.

[SCV]

Not having enough general io's is usually the most restrictive limiter to development boards.

I would suggest RS422/485 and a full H bridge DC motor driver if you have room!

[m.kaviani]

Not having enough general io's is usually the most restrictive limiter to development boards.

I would suggest RS422/485 and a full H bridge DC motor driver if you have room!

i think an step motor driver Is more useful. I am trying to make space on the board for
SMD step motor driver

[top204]

Looks like a nice board

Does it have a USB to serial device on board? And does the DTR or RTS pin of the device go to the PICmicrocontroller's MCLR pin, through a 470 Ohm resistor?

With this arangement, a bootloader can be created to automatically upload frimware to it by pulling the DTR or RTS pin low-high to reset the microcontroller. The USB also allows communication to a serial terminal on a PC without a serial port, when testing serial coms that would normally be used within industrial surroundings that still use standard seraal coms because they are very reliable, unlike USB or ethernet etc...

[gtvpic]

A few years ago I developed a card similar to a PLC equipped with PIC 18F8720.
In principle, this card had approximately 80 inputs and 64 outputs, for this it used MAX7300 I2C expanders. Hundreds of these cards were made and are still working.
I send PDF with the diagrams to be able to comment.
A greeting

[m.kaviani]

Looks like a nice board

Does it have a USB to serial device on board? And does the DTR or RTS pin of the device go to the PICmicrocontroller's MCLR pin, through a 470 Ohm resistor?

With this arangement, a bootloader can be created to automatically upload frimware to it by pulling the DTR or RTS pin low-high to reset the microcontroller. The USB also allows communication to a serial terminal on a PC without a serial port, when testing serial coms that would normally be used within industrial surroundings that still use standard seraal coms because they are very reliable, unlike USB or ethernet etc...

hi top204
yes, the board contains a USB to serial converter with rts and cts. of course it is possible to change IC to another one. if you have tested the schematic for bootloader
based on USB/serial converter, I will be happy to change this section. I was trying to make a free place for a double pole switch for the bootloader.
I found a new chip in the market ch340G instead of ch340e. it has dtr and rts.

[m.kaviani]

A few years ago I developed a card similar to a PLC equipped with PIC 18F8720.
In principle, this card had approximately 80 inputs and 64 outputs, for this it used MAX7300 I2C expanders. Hundreds of these cards were made and are still working.
I send a PDF with the diagrams to be able to comment.
A greeting

Very good. I did use the I2C I/O chip in one of my projects and it was very useful. the ideas that you used for rs232 and rs485 in a common port were interesting. I am going to remove the terminal and move mobbus to D-sub 9 pin. 

[top204]

I've used the CH340G in a few projects and it is a good little device, and extremely inexpensive. It will require an external 12MHz crystal. It also has signed Windows10 drivers. The CH340E is also a nice device that does not require an external crystal, but when I last looked at it, it did not have signed drivers for Windows 10, but it may have now. They both operate the same, so whatever is least expensive will work, but I've noticed the prices for the components from China are starting to increase.

For the microcontroller's MCLR pull-up resistor, use a 10K value and connect the MCLR pin to the CH340G's RTS pin via a 470 Ohm resistor. That way the bootloader can automatically reset the microcontroller before it bootloads it. If room allows, bring out all of the control lines from the CH340G device to a 2.54mm SIL header layout on the PCB, so they can easily be used if required.

[Simon]

Looks good, I have made a few very similar boards over the years and they've been great for testing.

I have to say that I hardly use many of the devices that I put on them and the most useful things is just having the pins of the microchip broken out.

A serial to usb converter is essential I would say and usb is a good way to power the board too.

Another simple but handy thing to add is a 10 turn pot, useful for testing an adc.

Also what I often do is add a few pinouts for different displays.


Here's an example:

[OG]

CH340G，CH340T，CH340C，CH340E，CH340B，CH341A，CH341T，CH341B，CH341C，CH341U
driver

http://www.wch-ic.com/downloads/CH341SER_EXE.html

CH340/CH341 USB to serial port Windows driver,
supports
32/64-bit Windows 10/8.1/8/7/VISTA/XP, Server 2016/2012/2008/2003, 2000/ME/98，Microsoft WHQL Certified, supports USB to 3 and 9 wire serial ports. Used to distribute to the end user with the product.


datasheet

datasheet

[m.kaviani]

Looks good, I have made a few very similar boards over the years and they've been great for testing.

I have to say that I hardly use many of the devices that I put on them and the most useful things is just having the pins of the microchip broken out.

A serial to usb converter is essential I would say and usb is a good way to power the board too.

Another simple but handy thing to add is a 10 turn pot, useful for testing an adc.

Also what I often do is add a few pinouts for different displays.


Here's an example:

thank you a lot, Simon. good job. i will put an RGB led on my board.

[m.kaviani]

CH340G，CH340T，CH340C，CH340E，CH340B，CH341A，CH341T，CH341B，CH341C，CH341U
driver

http://www.wch-ic.com/downloads/CH341SER_EXE.html

CH340/CH341 USB to serial port Windows driver,
supports
32/64-bit Windows 10/8.1/8/7/VISTA/XP, Server 2016/2012/2008/2003, 2000/ME/98，Microsoft WHQL Certified, supports USB to 3 and 9 wire serial ports. Used to distribute to the end user with the product.


datasheet

datasheet

Thank you OG

[m.kaviani]

Finally, I did finish my board by adding the FT800 port, USB to serial ( bootloader ), and merge rs485 to d-sub 9 pin serial port as well as ws2813 RGB led.
after the Iranian Norooz (new year) vacation, I will send it for lithography to make PCB, thank GOD.
    

[Simon]

That looks good!

I've not heard of the FT800 before, I'd assumed that would be a usb-serial chip but googling suggests a display controller??

One thing I noticed was the crystals are quite large, you can get much smaller smd crystals but maybe you are planning to fit sockets so they can be changed? They are also not very close to the pic and since it looks like there is room maybe they would fit a little closer?

I thought when when you mentioned a trip to Iran you'd be there for Norooz, have a happy New Year!

[m.kaviani]

Thanks, Simon.
FT800 is the TFT display controller that can handle 3" to 4.3" 500*500 resolution color LCD. the controller can use with I2C and SPI, but certainly, SPI is faster.
about crystals, the DIPs are cheaper in price. I will try to put the pic crystal as close as possible.
yes, I am living in Iran and Norooze is the beginning of the new year.

[m.kaviani]

It's interesting. whenever somebody left a new post and gives me a new suggestion, it opens a little room on my Board that can use for a new device.
there are two little rooms. has anyone a suggestion?

I have 10 days before lithography.