ATtiny85 + Arduino Fio + Wixel (as FTDI)

Development Boards Arduino
1

Hi!

I’ve been trying to program an “ATtiny85” with my “Arduino Fio”, using a Pololu Wixel as a FTDI to communicate to the Fio.

First, i plugged the wixel to USB and wrote to it (using “Wixel Configuration Utility”) the Wireless Serial App (http://www.pololu.com/docs/0J46/9.b) setting “baud_rate” to 57600, “serial_mode” to 3 and “framing_error_ms” to 5;

I did sucessfully program the “Arduino Fio” using the Wixel, with the following connection configuration:

Wixel…Arduino Fio

0_0(Arduino DTR)…DTR

1_6(TX)…RXI

1_7(RX)…TXO

3V3…3V3 + AREF

GND…GND

I also connected an (heartbeat) led with a resistor to pin D9 on Fio and to GND.

I checked “Tools, Boards, Arduino Fio”, “Tools, Serial port, COM6(Wixel’s serial port)”, “Tools, Programmer, AVRISP mkll” and had uploaded the “ArduinoISP” example to Arduino Fio.

Everything worked OK, the “heartbeat” start blinking. Perfect. :smiley:

Then i kept the above connections and plugged the Attiny85 to the breadboard, as follows:

ATtiny85…Arduino Fio

7(SCK)…D13

6(MISO)…D12

5(MOSI)…D11

1(RESET)…D10

8(VCC)…3V3

4(GND)…GND

I also connected another (error) led to pin D8 and GND on Fio.

Everything seems ok, so then i opened the “Blink” example, changed the line:

int led = 13;

to

int led = 4;

Then, i checked “Tools, Boards, ATtiny85 (internal 1MHz clock)”, “Tools, Programmer, Arduino as ISP” and tried to upload the sketch, but the error led always turns ON and the heartbeat stops blinking (stays ON too).

What i’ve done wrong? :cry:

I’ve also tried to use a Logic Level Converter between Arduino Fio and the ATtiny85 with no success, and then use it between Wixel and Arduino Fio, no success too.

Thanks in advance.

Product references:

Arduino Fio: https://www.sparkfun.com/products/10116

Logic Level Converter: https://www.sparkfun.com/products/11978

Wixel: https://www.sparkfun.com/products/10665

ATtiny85: https://www.sparkfun.com/products/9378

2

Forgot to mention: I also tried to write bootloader to ATtiny, with no success… :frowning:

3

One more thing, and i don´t really know if it is relevant: When i upload the sketch and the error happens, the red led on Wixel blinks quickly once, and only after that (but almost at the same time) the error led connected to D9 turns ON.

However, if i disconnect the RX pin from Wixel, the red led doesnt blink (only the error led on D9 turns ON), what make me suppose that the arduino is sending an error code back to it, a bad signal or something like that. That´s why i tried to use an logic level converter between them, but no use.

I think that is something wrong/missing at the connections between arduino and attiny or with the ArduinoISP code to work with arduino fio…

4

EUREKA!!!

Searching around to learn more about the Arduino IDE, accidentally, found the problem!

By enabling “File, Preferences, Show verbose output during: upload”, i was able to see the following message when i try to upload: “Overriding Baud Rate : 19200”

The tutorials which says that the baud rate has to be 57600 are wrong, as its waiting for for sync at 19200.

Changed the baud rate at Wixel’s “Wireless serial app” and at windows Device Manager (COM6 in my case), added an 0,1uF capacitor between RESET (DTR-GRN pin on Arduino Fio) and GND to auto-reset and everything flows perfectly now.

:smiley: :clap:

5

Great job! You should post a summary about this on the Arduino and Pololu forums, in case anyone there tries the same approach. Take some more credit.

6

Thanks, jremington!

I’ve been quite outta time these days, but i’ll do so tomorrow.