While trying to open a chinese camera pen, unfortunately the PCB inside it got damaged. Few of the PCB traces got cut and it became useless. After few days, I removed an 8 pin IC with SO8 package from the PCB. I was curious to know what it is, so I googled the part number 25FW406A but I couldn't find any exact match. I found some part number similar to that and I concluded that it is an SPI flash. Later I got a datasheet from 'ON semiconductor' for a similar part -LE25U40CMD which is a 4M-bit SPI flash memory. I soldered the IC on a common board, powered it with 3.3v and interfaced it to a TI stellaris launchpad via SPI port. According to the datasheet the SPI port need to be initialized in mode 0 or 3. I tried few commands listed in the datasheet and got proper response from the chip, the CHIP ID doesn't matches but that is expected because it is not the same part. I wrote functions for erasing, reading and writing the flash memory and tested it successfully using the launchpad.
Then I thought of making an audio player using this chip which can play 8K mono wav file for around 1 minute. I selected Attiny13 microcontroller for this project. It is always fun to do some thing with limited resources. Attiny13 MCU is having 1KB flash and 64 bytes RAM. Also it is an 8 pin MCU. There are 5 GPIOs. I don't want to change the reset pin as a GPIO because I want to program it via ISP while developing the firmware.