Dev board - Page 1
Forum section: electronics / projects

author: House91320
author_rank: Regular Contributor
timestamp: November 08, 2010, 12:52:23 am
content: Hello i am working a a dev board based on the dsPIC30F4013 and because this is my most complicated schematic i was wonder if you the eevblog forum could check it.https://www.eevblog.com/forum/index.php?action=gallery;sa=view&id=12

author: allanw
author_rank: Frequent Contributor
timestamp: November 08, 2010, 01:18:19 am
content: Needs more caps. It's good practice to put one cap per supply rail. ie. you'll want separate ones between pins 11 and 12, pins 20 and 21, pins 31 and 32, pins 39 and 40. AVDD should not be connected through a resistor.Also the connections on SV6 should have junctions. I'm not sure if they're being made.You'll want a pull-up resistor on the reset pin.All of these things should be covered in some appnote or reference schematic.Looks mostly good other than that though.

author: EEVblog
author_rank: Unknown
timestamp: November 08, 2010, 01:27:31 am
content: Why do you have two +5V voltage regulators?Dave.

author: JohnS_AZ
author_rank: Frequent Contributor
timestamp: November 08, 2010, 01:54:03 am
content: You have the power coming into J1 on the ring instead of the tip (center) ... does that actually match your power source?

author: House91320
author_rank: Regular Contributor
timestamp: November 08, 2010, 02:28:55 am
content: no its a 5v and a 3v

author: House91320
author_rank: Regular Contributor
timestamp: November 08, 2010, 03:36:36 am
content: thank you for the help i have fixed the problems

author: EEVblog
author_rank: Unknown
timestamp: November 08, 2010, 04:25:32 am
content: Quote from: House91320 on November 08, 2010, 02:28:55 amThen you have your labeling wrong, they are both labeled 5VDave.

author: House91320
author_rank: Regular Contributor
timestamp: November 08, 2010, 05:14:07 am
content: o didn't notis that thank you

author: Mechatrommer
author_rank: Super Contributor
timestamp: November 08, 2010, 12:04:00 pm
content: i'm not really an expert into commenting the technical thing, just trivial thing such as i have to keep rotating my head to the left to read the vertical labelling and some of it superimposed on the schematicdrawing component on the wire line such as S1 near bottom right is not a good idea either. nothing serious, its just it will be more difficult for other people to read, esp beginner like mejust IMHO.

author: TheDirty
author_rank: Frequent Contributor
timestamp: November 08, 2010, 12:15:12 pm
content: So, is the voltage supposed to be 3V or 5V? If it's 3V, the MAX232 won't work. You'll need to use something like the MAX3232. Also the V+ and V- for the MAX232 datasheet shows a cap between the pins and GND/Supply.

author: TechGuy
author_rank: Regular Contributor
timestamp: November 12, 2010, 07:17:40 pm
content: How are your programming the MCU? I didn't see an ICSP port. I see that MCLR is not connected to anything except for the reset button. You need a pull up resistor on MCLR to prevent spurious resets. Read the datasheet (See Page 151 for MCLR) for the MCU so you can properly wire up the MCLR and set up the ICSP port for in-circuit programming and debugging.You also do not need to connect the RS232 RXout to the interrupt INT2. the UART module has an internal interrupt signal for triggering interrupts when Serial IO is received. Remember that Serial I/O is serial not parallel, INT2 will trigger for each and every Bit sent, not per byte!I would also recommend some on-board status LEDs that you can flash using a couple of pins on one of the IO ports. This will help you make sure your MCU is running or performing as you expect. Its going to take a bit of trial and error before you get the UART working correctly if you are new to Microchip MCU's. So before you get UART working you can use the LEDs as status indicators.I would google for some PIC30 schematics or look for Appnotes so you can see how to set up a PIC30 MCU. Schematic doesn't have to be for your exact MCU ie (dsPIC30F4013), any model in the 4000 series is probably close enough, for the common pins (MCLR, ICSP, Power, UART, etc).