tooth_tunes_hack

http://www.grandideastudio.com/wp-content/uploads/toothtunes_slides.pdf

Notes

Petit FAT filesystem (http://elm-chan.org/fsw/ff/00index_p.html)
- only pertains to the embedded side
  - the SD card itself can be formatted to:
    - FAT12, FAT16 and FAT32
Converting MP3/etc to correct audio format (WAV format (Microsoft RIFF), 8/16-bit, mono, 8-48kHz)
- http://elm-chan.org/works/sd8p/report.html
- I only tried:
  - 8-bit mono, 8000kHz
    - ffmpeg -i input.mp3 -acodec pcm_u8 -ac 1 -ar 8000 output.wav
      - PCM unsigned 8-bit
      - I didn't try s8 PCM signed 8-bit ... but now I wonder if it would improve the audio quality
- 16-bit, 16 kHz
  - ffmpeg -i input.mp3 -acodec pcm_s16le -ac 1 -ar 16000 output.wav
    - PCM signed 16-bit little-endian
- https://trac.ffmpeg.org/wiki/audio%20types

-- Programming hex file --

I didn't recompile, just used what Joe Grand provided
- sudo avrdude -P /dev/ttyACM0 -c avrisp -b 9600 -p t85 -U flash:w:sd8p_mo.hex:i

avrdude: AVR device initialized and ready to accept instructions

Reading | ################################################## | 100% 0.05s

avrdude: Device signature = 0x1e930b (probably t85)
avrdude: NOTE: "flash" memory has been specified, an erase cycle will be performed
         To disable this feature, specify the -D option.
avrdude: erasing chip
avrdude: reading input file "sd8p_mo.hex"
avrdude: writing flash (6374 bytes):

Writing | ################################################## | 100% 8.80s

avrdude: 6374 bytes of flash written
avrdude: verifying flash memory against sd8p_mo.hex:
avrdude: load data flash data from input file sd8p_mo.hex:
avrdude: input file sd8p_mo.hex contains 6374 bytes
avrdude: reading on-chip flash data:

Reading | ################################################## | 100% 5.84s

avrdude: verifying ...
avrdude: 6374 bytes of flash verified

avrdude: safemode: Fuses OK (E:FF, H:DF, L:62)

avrdude done.  Thank you.

sudo avrdude -P /dev/ttyACM0 -c avrisp -b 9600 -p t85 -V -U lfuse:w:0xe1:m -U hfuse:w:0x7d:m

avrdude: AVR device initialized and ready to accept instructions

Reading | ################################################## | 100% 0.05s

avrdude: Device signature = 0x1e930b (probably t85)
avrdude: reading input file "0xe1"
avrdude: writing lfuse (1 bytes):

Writing | ################################################## | 100% 0.06s

avrdude: 1 bytes of lfuse written
avrdude: reading input file "0x7d"
avrdude: writing hfuse (1 bytes):

Writing |                                                    | 0% 0.00s ***failed;  
Writing | ################################################## | 100% 0.16s

avrdude: 1 bytes of hfuse written

avrdude: safemode: hfuse changed! Was 7d, and is now 5d
Would you like this fuse to be changed back? [y/n] y
^C

Issues encountered

avrdude invalid device signature
- Solutions considered:
  - Arduino ISP to ATTiny85 connection issue?
    - this seemed to be the issue, changed the Arduino ISP code to use d10 for SS (also see the table below, I was using a Leonardo)
    - got code changes for using alternate pins from here:
      - https://www.instructables.com/id/Arduino-Leonardo-as-Isp/
  - Default fuses from manufacturer expect 16MHz crystal?
    - built a high-voltage fuse resetter
      - HV programmer reset fuses to(LFUSE: 6A HFUSE: FF)
        
        http://www.engbedded.com/fusecalc/ -- says 6A and FF are
      - schematic based on this site's image (also shown below with Arduino ISP connections in Red, for clarity when it comes to actual program code flashing)
        
        http://www.electronics-lab.com/recover-bricked-attiny-using-arduino-as-high-voltage-programmer/
        
        https://arduinodiy.wordpress.com/2015/05/16/high-voltage-programmingunbricking-for-attiny/

-- SPI Connections --

from https://www.arduino.cc/en/Reference/SPI The following table display on which pins the SPI lines are broken out on the different Arduino boards:

Arduino / Genuino Board	MOSI	MISO	SCK	SS (slave)	SS (master)	Level
Uno or Duemilanove	11 or ICSP-4	12 or ICSP-1	13 or ICSP-3	10	-	5V
Mega1280 or Mega2560	51 or ICSP-4	50 or ICSP-1	52 or ICSP-3	53	-	5V
Leonardo	ICSP-4	ICSP-1	ICSP-3	-	-	5V
Due	ICSP-4	ICSP-1	ICSP-3	-	4,10,52	3,3V
Zero	ICSP-4	ICSP-1	ICSP-3	-	-	3,3V
101	11 or ICSP-4	12 or ICSP-1	13 or ICSP-3	10	10	3,3V
MKR1000	8	10	9	-	-	3,3V

Note that MISO, MOSI, and SCK are available in a consistent physical location on the ICSP header; this is useful, for example, in designing a shield that works on every board.

-- Actual connections used --

ATTiny85	Arduino Leonardo
MISO pin 6	ICSP pin MISO
MOSI pin 5	ICSP pin MOSI
SCK pin 7	ICSP pin SCK
RESET pin1	digital pin 10
GND	GND
Vcc	5v

nmz787/tooth_tunes_hack

tooth_tunes_hack