Society of Robots - Robot Forum
Electronics => Electronics => Topic started by: Trumpkin on September 17, 2008, 09:37:39 AM
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I finally finished the schematic of the Atmega32 MCU board i've been working on. Can someone look over it to make sure everything is OK? Thanks.
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If you have a boot loader then it's fine...
If have the boot loader can you please upload????
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You may need more decoupling capacitors. Specifically one very near to FTDI chip.
Where is the power for VCC and VDD? As far as I can see output of 5V regulator is not connected to VCC or VDD.
Looks like you don't intend to use built in PWM outputs from AVR. I don't have the datasheet right now, but at first look seems like pins connected to H-bridge won't support the PWM outputs.
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Where is the power for VCC and VDD?
VCC will be connected to the regulator while VDD will be connected to a seperate battery pack for the motors, that is right isn't it? :P
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If you have a boot loader then it's fine...
If have the boot loader can you please upload????
Yes - you don't show any ISP header - so how will you program it?
Also - your circuit shows a power supply switch. Make sure the switch is big enough for the current used by the mcu + servos + the motor controller.
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you don't show any ISP header - so how will you program it?
http://hubbard.engr.scu.edu/embedded/avr/ftisp/
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Dude, unless you have a bootloader, you must use SPI. IIRC, the bitbang pins are located on CBUS. No data from CBUS (except leds) goes to the SPI pins. Or maybe the bitbang is on RX/TX, still, those pins go to the MCU TX/RX.
You say you don't have a bootloader. So, how is this thing programmed?
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Couldn't I just modify Admins bootloader?
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you also don't really have good accomodations for mounting holes. Your wire 14 for instance runs along the edge of the profile. You should consider moving it and 15 to be side by side tighter to 4. you should probablly also clean up the directions for 1,2,3,4 since they're unnecessarily crossing (same with 15).
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I'm not going to make printed circuit board of it, just so you know.
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You can, but you'll need to modify the PC software to interact with it.
I really dig the bitbang outputs of the FT232R. I wonder if avrdude can be configured to use FT232R (CBUS pins) as a programmer. Anyone knows?
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Take a look at this website http://hubbard.engr.scu.edu/embedded/avr/boards/ he uses ftisp to program his AVRmini v4.0. He even has a schematic of the board.
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I'm sorry if I seem dense :P but to get ftisp to work do I just connect the CTS, DSR, DCD and RI lines from the ft232R to the Atmega32?
like so:
CTS to MOSI
DSR to SCK
DCD to MISO
RI to RESET
Would I also need to connect the TXD and RXD lines???
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You want TX and RX anyway, for a USB/COM emulator. Don't need them for SPI programming though.
I'm not sure about the rest of the pins go, check with ftisp.
Also, another cool IC is FT2232, which has hardware SPI (and thus, improved programming speeds).
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Right now, it would be really nice if someone could just tell me if I have it right or not. :D
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well you can just buy a set of solderless breadboards and have at it! the components you're talking about don't seem to be expensive enough to prohibit a very cautionary approach. but that's my opinion.
you're always going to find errors in design or at least improvements after you've built the prototype. then you'll have issues moving from the solderless breadboard to a protoboard. in the latter i highly recommend having at least 3x the number of components you require for your target product. This allows you the margin to have a prototype on the solderless breadboard (that you can keep around to look at) and also to build a 2nd improved board at the protoboard stage (if you haven't smoked things). also take lots of pictures and document your changes on your drawings as you go.