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i am new to (assembly) spi communication commands

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Full Member level 2
Feb 24, 2011
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This is veera reddy, i have a problem with spi commands in my application, i am trying to log sensor data from sensor tag. here sensor ic chip is mlx90129 it is located on the evb90129 board. this chip having internal eeprom there is noproblem when reading internal memory. this evalution board having external eeprom to store more data, for that i am using spi communication to log the data from external memory. can any one suggest me which comands is useful for that data logging from external memory. data sheet available at MLX90129.


  • EVB90129.pdf
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  • MLX90129_Datasheet_March_2010.pdf
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  • AN2_MLX90129_Data_Logging.pdf
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What controller you're using manage the MLX9109? Attached is an appnote dealing with SPI communications with MLX91029 with sample code for a variety of controllers.


  • AN1_MLX90129_SPI_Communication.pdf
    521.9 KB · Views: 92

The EVB90129 can be accessed and controlled through a contactless (RFID) or a contact (SPI) interface. The RFID access to the MLX90129 and the related commands are compliant with the ISO15693 standard. The SPI and other digital inputs/outputs from the MLX90129 are connected to an 8-pin connector of the EVB90129. This allows easy connection to a microcontroller.

You need to select a controller SPI to manage the MLX90129 via SPI.

thank you very much for replying, i am using atmel coporation atmega168 8bit controller, and i am using hyperteminal to read and write commands for reading data from sensors. in datasheet AN2_MLX90129_data_logging.PDF ther is a procedure to connect external memory and mlx90129 by using spi communication(section3.4) in that set the following configuration in eeprom adress #0D=0x0629 and #0E=0203. i cant understand these commands how to store in external eeprom and how to read, via spi communication commands.
thank you,
best regards.

Try to understand the different operation and respective SPI modes provided by MLX90129. It can work either as standalone device and SPI master, or be controlled as SPI slave by an external microprocessor. In the latter case, the device won't talk to an external memory.

now i tried to read and write to internal memory of mlx90129 and i communicate with mlx and external microcontroller and also i succeded to log data from internal memory. but the problem is now i want to log data from sensors and i used external SPI EEPROM to store logged data, i set the required configuration for that mode but i tryed to read data nothing will happend.there is a problem . and i tried to connect directly MCU to external memory still i cant write or read to external memory so any body suggest me how to write enable to external memory by using spi communication. i am using CAT25128(128kB) external eeprom.

can any body help me , i am reding hexa decimal value from mlx chip like 9BD0, how can i convert this to temperature because i am reading from temprature sensor.

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