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I have a project I'm working on that involves an nrf51822 communicating with the optical sensor from a mouse. The pinout of the opical sensor seems similar to the ADNS2620, but the exact datasheet is not available. The datasheet for the ADNS2620 seems to basically say (but not explicitly say) that it uses I2C - unless I'm not understanding it correctly.

I've established an i2c scanner on my nrf51822, and it is (as far as I can tell) properly scanning each address (1-127) to find a device, but is receiving to response. I'm left to question if the optical sensor even communicates over i2c - and if not, where do I go from here?

Pointers appreciated. Thanks.

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I'm left to question if the optical sensor even communicates over i2c

It is not I²C. Clues:

  • Maximum frequency of SCLK: 2 MHz.
  • No resistors on the bus lines in the application schematic

The protocol is actually SPI, with MISO and MOSI connected together on the same pin.

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  • \$\begingroup\$ Would you guess that my mystery chip is configured similarly? Can you give some documentation pointers? \$\endgroup\$ – Helpful Aug 15 '17 at 3:14
  • \$\begingroup\$ Note that more modern mouse chips would speak USB directly, which prevents using the NRF51x to talk to it. \$\endgroup\$ – Turbo J Aug 15 '17 at 3:19
  • \$\begingroup\$ My mystery chip came from a wireless mouse and it communicated with some sort of wireless module, so I'm hopeful I'll be able to read off it. \$\endgroup\$ – Helpful Aug 15 '17 at 4:05

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