FTDI ATmega
FTDI-atmega
This is the documentation page for the FTDI-atmega PCB.
overview
The FTDI-atmega PCB has an USB connector and a 20-pin IO connector. The brains of the PCB is an ATmega168 chip.
External resources
pinout
The 20 pin connector is connected as follows
| 1 | GND |
| 2 | GND |
| 3 | PC3 |
| 4 | PC2 |
| 5 | PC1 |
| 6 | PC0 |
| 7 | PB5 |
| 8 | PB4 |
| 9 | PB3 |
| 10 | PB2 |
| 11 | PB1 |
| 12 | PB0 |
| 13 | PD7 |
| 14 | PD6 |
| 15 | PD5 |
| 16 | PD4 |
| 17 | PD3 |
| 18 | PD2 |
| 19 | VCC |
| 20 | VCC |
- led1 is connected to VCC (the top one, called led2 on V7.0)
- led2 is connected to CBUS0 (FT232RL) PC -> AVR activity
- led3 is connected to CBUS1 (FT232RL) AVR -> PC activity
- led4 is connected to PC5
- led5 is connected to PC4 (absent on V7.0)
Arduino Pinout
When using the Arduino IDE, the layout of the header is as follows:
| GND | GND |
| A3 | A2 |
| A1 | A0 |
| 13 | 12 |
| 11 | 10 |
| 9 | 8 |
| 7 | 6 |
| 5 | 4 |
| 3 | 2 |
| V+ | V+ |
- Unlike a regular arduino, the onboard LED is connected to pin A5. This means pin 13 is free for regular use.
- Pin 0 and 1 are used for the COM interface just like a regular arduino.
- Pin 3, 5, 6, 9, 10 and 11 support PWM (analogWrite), just like a regular arduino.
programming
This section describes how you get your program into the processor.
Linux
You can program the processor using any ICSP programmer that you might have. In that case, the jumper SV1 should then be in the upper position (away from the ICSP connector).
Or you can program it with the ftdi bitbang programmer included on the board.
Here is the documentation: http://www.geocities.jp/arduino_diecimila/bootloader/index_en.html
The ftdi-bitbang programmer-driver for avrdude is not included in the standard avrdude program. The reason is that the patch uses the ftdi library FTD2xx and not the open source libftdi.
In the avrdude bug tracking system another patch is doing the rounds, but that one is really slow because it doesn't exploit the ftdi's synchronous mode.
A precompiled avrdude version can be downloaded here: http://www.bitwizard.nl/avrdude.zip . The zipfile contains "quick and dirty" instructions to replace the avrdude binary in /usr/bin with a script so that when "arduino IDE" calls it, the program gets programmed into the board.
TODO: port the fast ftdi bitbang code to libftdi and submit to avrdude.
windows
See the linux section above.
writing programs
The chip is an ATmega168. http://www.atmel.com/dyn/resources/prod_documents/doc2545.pdf
future hardware enhancements
Provide a 3- or 4-pin header with the i2c pins (to communicate with wiimote and other peripherals). The leds need to be disabled for this to work. :-(
future software enhancements
Changelog
7.0
- Initial public release
7.1
- Added decoupling capacitor for FTDI 3.3
- Added SJ for arduino compatibility.