ATtiny84, FTDI FT232RL, SoftwareSerial does not work

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1

Dear Arduino Community,
Google wasn't a help.... so this is my question: What is wrong with my Circuit or Code?

Short Description: the ATtiny84 should communicate via FT232RL (origin. FTDI) and using "SoftwareSerial.h" to the Host (PC). Please take a look at the Picture!

Circuit: ATtiny84 with external 16MHz crystal, the ceramic capacitators conncted from crystal pins to GND are 10pF, the ceramic capacitator connected from "DTR" to "/RESET" is 100nF. The resistor connected from "/RESET" to Vcc is 10K.
I flashed the code below by Arduino as ISP successfully (I tested also the standard Blink Sketch and it worked).
The Host (PC, Win 7 x64 prof.) has successfully recognized the FTDI chip and installed the driver successfully.

Result: I get nothing! Not even a corrupted byte!
What I already have tried and did not work:

  • Removed R1
  • Removed R1, and C3, so DTR was connected directly to /RESET
  • Removed R1, C3 and the Wire from DTR to /RESET => so DTR and /RESET were not connected

I also tried other "BAUD" rates below 9600 (also in combination to the list of tries above)... but none of them worked.

I have several FT232RL-Break-Outs, so I changed it... also in combination of diff. BAUD rates and the list of trys above... did also not work.

I am using the same FT232RL-Break-out with ATmega 328P with the same circuit, and it works.

Is there anyone who has already experienced with ATtiny84/44, SoftwareSerial and FT232?

Thank you in forward for your help!
Kindly Regards...

#include <SoftwareSerial.h>

//                              RX, TX.
SoftwareSerial mySerial( 2, 3 );


void setup()
{
    mySerial.begin(9600);
}

void loop() 
{
    mySerial.println("ATtiny84");    
    delay(1000);
}

ATtiny 84 FT232_Steckplatine.jpg
ATtiny 84 FT232_Steckplatine.jpg570×1020 143 KB

2

(deleted)

3

FATAL_ERROR:
Please take a look at the Picture!

2faf4d4a5abc821ff23091bbf36997976742e825.jpg
2faf4d4a5abc821ff23091bbf36997976742e825.jpg570×1020 143 KB

Before anyone else says it, that is a bad layout.

You should jumper pins 1 and 14 to the breadboard columns just next to them with minuscule jumpers so that the 0.1 µF capacitor that you have omitted can be placed directly between those pins. Similarly, the two 10 pF capacitors should jump directly across to a column immediately to the right of this which can then be grounded directly to the new pin 14 column. Connecting the crystal pins to more than one column increases the loading capacitance on the crystal substantially; it is already reported that the capacitance of the breadboard itself is often sufficient loading capacitance and using the specified capacitors in addition can actually make it not work!.

That said, whether that is related to your current problem is perhaps not likely, but unless you follow correct practice you can hardly expect things to work anything like reliably.

FATAL_ERROR:

  • Removed R1
  • Removed R1, and C3, so DTR was connected directly to /RESET
  • Removed R1, C3 and the Wire from DTR to /RESET => so DTR and /RESET were not connected

A set of random experiments with no sensible justification whatsoever. :roll_eyes: You need to correct any errors, not remove working parts.