Hello, I'm trying to transfer my arduino uno project to a PCB. I made a schematic on CircuitMaker and was hoping someone here can kindly verify my connections and my work. It is my very first time doing something like this, so I am unsure about the work I've done.
I require a USB to both power up the atmega328 and to send serial data to and from a PC, so I am using a FT232RL chip. I am mostly concerned about the connections from the chip to the atmega328 UC. I tried my best to follow SparkFun's FT232 breakout board schematic, but it got confusing for here and there. I tried my best to refer to the FT232 datasheet as well.
Any help would be most appreciated!
Thanks
Schematic.PDF (199 KB)
RTS from FT232 is not going anywhere, you can delete that.
FT232 Reset is not connected. Should connect that High or Low as needed. Don't leave that pin floating.
Add more 0.1uF caps to VCC/AVCC - one for each pin.
Add a diode from Reset (anode) to +5 (cathode) - will dissipate any spikes in voltage from reset switch - see current Uno design. 1N4148 is all you need.
Why take ESD Button to one pin, and ESD Voltage someplace totally different on the chip? I'd go to two adjacent pins.
Thanks for your reply CrossRoads! Here's the following changes I made:
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I've included a total of five 0.1uF caps between VCC and GND (1x for USB connector Vcc, 2x for FT232 Vcc and VCCIO, and 2x for atmega VCC and AVCC).
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Pulled RESET pin of FT232 to 5V
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Added diode between 5V and GND
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Deleted RTS from FT232
The atmega is looking for a digital state from the ESD button pin, so I am mapping that to the UNO's digital pin 5. The ESD voltage pin will be reading an analog voltage once the ESD button goes HIGH. Since I'll be reading an analog voltage, I've mapped it to analog pin A0 of the UNO. Sorry, this is my first time playing with an Arduino as well, so there might be a few choices I made that might not make sense. If there's a better solution, I'd be more than happy to hear it!
I've attached an updated copy of the schematic.
Also, I am wondering what are the MH1 and MH2 connection from the USB connector?
Thanks for your help!
Schematic.PDF (216 KB)
shameless bump. Would be great if I can get one more verification. Thanks!
Diode is in wrong place. Needs to go from Reset (anode) to +5 (cathode).
ESD button, could go to pin 24. Analog pins can be used for digitalRead also.
MH1, MH2, could be shield pins of the connector, connect to Gnd if so.
CrossRoads:
Diode is in wrong place. Needs to go from Reset (anode) to +5 (cathode).
ESD button, could go to pin 24. Analog pins can be used for digitalRead also.
MH1, MH2, could be shield pins of the connector, connect to Gnd if so.
Thanks CrossRoad, I've fixed the diode mistake. Other than that, does the schematic look okay?
Thanks Again. It's greatly apprecaited