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FTDI Connection And Programming  XML
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esa1966



Joined: 19/02/2015 13:48:52
Messages: 3
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Dear,
I just received the Anarduino Mini-Wireless and the Anarduino-FTDI USB<>UART Breakout Board.

I have several question :

1) Do you have the Schematic for the FTDI as I try to understand the Power Switch on FTDI board.
I connect the FTDI with a USB cable to the computer and I suppose, the power will come from the USB.
When I select +5V, I measure 5V between GND and VCC.
When I select 3V3, I don't measure a voltage between GND and VCC and Logic level on RX/TX/DTR is always 5V.
Is it normal?

From a schematic (https://github.com/adafruit/FTDI-Friend/blob/master/ftdifriendsch.png) the chip FT232RL has a PIN VCCIO to adapt the IO level volatge..

2) I suppose, that I can connect the MW to the FTDI and it will be powered by the USB.
Does the VCC coming from the FTDI made to power the MW?
I select 3V3 on FTDI and when I connect the MW, I have +/- 2.5 V between GND and VCC on FTDI (MW is not powered).
Is it a return from other PIN signal (RX/TX)?

3) I suppose, I can't select 5V because VCC doesn't go through the Regulator.
The regulator work with VIN.

In other words, must I absolutely power the MW through VCC.


4) In Arduino 1.6.0, what can I select for the board and for the Programmer?

thank for your help
Best Regards


This message was edited 1 time. Last update was at 19/02/2015 14:35:32

esa1966



Joined: 19/02/2015 13:48:52
Messages: 3
Offline

HI,

I have powered the MW and realized that VCC on the JP1 (FTDI connection) is in fact VIN.
If I put 5VDC on VIN, I also have JP1 PIN VCC with 5VDC.
It's not clear on the schematic.

Point 2 : If I put 5VDC on VIN, then the logic for RX/TX is at 3V3 DC.
It's normal because the µP is powered by 3.3VDC.

Question for FTDI :
Possibility 1 :
If I select 3V3 on FTDI then the MW won't be powered by the FTDI (as no voltage is present on the output of the FTDI VCC PIN).
I have to power the MW with an external power.
But the Logic level on RX/TX/DTR is always 5V.
Can I connect to MW?

Possibility 2 :
If I select 5V, then the FTDI will power the MW. I don't need an external power.
But LOGIC LEVEL will be 5 V on RX/TX/DTR.

Question : is it a risk to blow the µP or is it 5V tolerant even if µP is at 3V3DC?

stevech



Joined: 07/07/2014 18:07:27
Messages: 91
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This USB/Serial board with FTDI pinout has a switch to go between Vcc = 5V and 3.3V.
The mega328p seems to be 5V tolerant on the UART.

http://www.anarduino.com/details.jsp?pid=149

Rick



Joined: 30/05/2014 22:08:56
Messages: 93
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Greetings, and thanks for your inquiry.

The Anarduino FTDI features a switch to select between 3.3 and 5.0V.

Most ftdi-based 3.3v units out there use the 3.3v output of the ftdi chip, which has maximum rating of only 50mA. This could be an issue--depending on what you have connected to it.
Our FTDI board derives the 3.3V directly from the 5.0V USB source, via an MCP1703 LDO 3.3V regulator, which gives you 3.3V at 250mA.
One possible issue that someone brought up, is the RX/TX would still operate at 5V (since the ftdi chip mode is still selected as 5V). While this is NOT an issue for any of the arduino compatible ATmega328 chips, and several other MCU's due to their gpio 5V tolerance, it could pose an issue if your are using an FTDI in 3.3V mode connecting to some ARM uart, whose pins may not be 5V tolerant. The current physical format of the FTDI is quite small, but needs some updates to be better conducive for use with either of our pick-n-place machines. We've intended to do a revision of this board for quite some time now, but it admittedly is still several items down on the priority list. We didn't think much of this initially, as it was intended for use in the arduino environment, but clearly this type of device could be useful for other things as well---thus the desire to improve on it.
Hope that helps, and thanks everyone for your participation.
All the best..
-Rick

esa1966



Joined: 19/02/2015 13:48:52
Messages: 3
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Hi,
Thank a lot for your explanation.

So, it seems that my FTDI has a problem because with the switch on 3v3 there is no voltage on the FTDI VCC PIN (nothing connected on FTDI).
That's why I asked the schematic to control what happen.

Point 1 : FTDI VCC output
In my point of view, it's not necessary to have a "MCP1703 LDO 3.3V regulator" on the FTDI board.
A Output of 5 Volt is enough as there is already a regulator on your MW that power the µP at 3v3.

Point2 : MW Schematic JP1
In fact, I was wondering because the MW schematic indicate VCC and not VIN on JP1.
So, I tough I need to set the FTDI on 3v3.
But it's not the case and the schematic might be adapted : "JP1 VCC" changed to "JP1 VIN" as it's really connected to VIN and not VCC.

Point3 : FTDI Switch.
Because I don't have the schematic and my FTDI doesn't deliver a output voltage with the switch on the 3V3 position I though that the switch is more like a "5 V INTERNAL POWER" and "EXTERNAL POWER"
I mean that the FTDI can power the MW or the MW can be powered externally.
That's how I will use it and I think it's a good feature.
In my case this switch can be labeled "Internal Power"/"External Power"
Design remark : It could be a good feature to authorize an external power. A JUMP could be added in serial with VCC output. Or if the regulator is suppressed, then the switch can do that work.

Point 3 : RX/TX level voltage.
As there is a regulator on the MW Arduino, then the µP will be powered with 3V3. And the µP RX/TX is at 3V3.
It seems logic that the FTDI you provide must be compatible with your MW.
While I understand that the µP is 5 V tolerant, that doesn't mean the trigger level will be correct.
So I have modified your FTDI to connect the FT232RL PIN 4 to PIN17 (I cut the connection to 5VCC).
Design remark : If there is a 3V3 output on the FTDI then the PIN 4 could be connected to the PIN VCC output so it will change the RX/TX level accordingly to the voltage output.


This is a feedback how I begin in the world of MW.
And as a beginner I'm certainly worrying too much.

Eric

This message was edited 1 time. Last update was at 22/02/2015 06:35:20

Rick



Joined: 30/05/2014 22:08:56
Messages: 93
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Thanks esa, good points as well.

P1) You're absolutely correct in regards to the MW, but that's only one type of product. I have several others that don't have a built-in LDO (and I'm sure there may be others out there with similar circumstances). I had built this board for my own project consumption, but then several people asked to buy it, and thus it emerged. Also, keep in mind that this was a few years ago I popped this board out. I occasionally think of improving it, but then there are soooo many other ideas to chase after.

P2) I'm in the process of rebuilding the MW portal page, which will have all the schematics to the various versions available. The schematic posted on that page is the original version of the MW-12B/CW, which had VCC on the FTDI header. I noticed this was less than optimal, so ALL other versions of MW have this as a VIN pin. NOTE that ALL newest versions of MW-12B/CW also have this pin as VIN.

P3) here you go...


No worries...

All the best..
-Rick

This message was edited 3 times. Last update was at 22/02/2015 23:55:41

johanneswiig



Joined: 14/04/2015 14:07:00
Messages: 4
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Hi,
I just got my shipment of MWs. I'm trying to program a MW (RFM69 based) with the sample code TGateway using a USB BUB II ( http://moderndevice.com/product/usb-bub-ii/ ) but I get this error:

avrdude: stk500_getsync(): not in sync: resp=0x53.

When just running the serial monitor I do get the output from the MW from the preloaded code, testing the RTC and memory etc.
I have no problem programming a Moteino R4 with the same setup, and I guess I assumed it would work the same with the MW.

What am I missing?
Would be good to know if anybody else have been able to program the MW with the USB BUB II.

Grateful for insights!
johanneswiig



Joined: 14/04/2015 14:07:00
Messages: 4
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I seem to be able to upload the code using these setting in the Arduino IDE:

Tools > Board > Arduino Pro or Pro Mini
and then set:
Tools > Processor > ATmega328 3.3V 8 MHz

and also
Tools > Board > Arduino Nano
with
Tools > Processor > ATmega 328.

However, it will not upload code to two other similar boards (not LoRa),
Here I get various avrdude error messages:
avrdude: stk500_getsync(): not in sync: resp=0x30

avrdude: stk500_getsync(): not in sync: resp=0xee

could I have messed up the bootloader? What is the procedure to burn the proper bootloader for the MW?
stevech



Joined: 07/07/2014 18:07:27
Messages: 91
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those boards' bootloader use a different baud rate?

pretty hard to damage a bootloader without using an ISP wired up to the AVR.
johanneswiig



Joined: 14/04/2015 14:07:00
Messages: 4
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hey stevech, and other prominent Anarduino fans,
I'm not sure about the differences of the baud rates on the bootloaders but I'd be surprised if they turn out to be different.

I'll keep working on this with the LoRa boards since they work. But I'm still wondering why the Arduino IDE can't program the MW using the Tools > Board > Arduino Uno,
which works fine with Moteino R4 and booth use Atmega328P..
stevech



Joined: 07/07/2014 18:07:27
Messages: 91
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what baud rate is the IDE using? 115200? It may be that some bootloaders are at 57600
stevem



Joined: 21/04/2015 14:54:06
Messages: 3
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I am brand new to Anarduino and was having difficulties in connecting via the PL2303 Usb cable. Using the Arduino IDE I was using the "Pro or ProMini" board, but with the 3volt (8 MHz processor), assuming that the Anarduino Mini is a 3v3 board. I found that the Serial Monitor baud rate ran at twice the speed as was designated in the Serial.begin statement in the sketch (eg. 57600 in the sketch required a setting of 115200 in the Serial Monitor). Selecting the 5v, 16 MHz processor in the IDE solved the Serial Monitor problem as well as the erratic behavior of the I2C sensor.

This message was edited 1 time. Last update was at 25/04/2015 19:09:04

 
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