Seabirds > blackbox.
--- In "cheezy072000" <> wrote:
>
> I am currently using the TS7200 with an SPI peripheral (ADXL345
> accelerometer) and am having huge problems reading multiple bytes of data on
> a single transmission.
>
> My accelerometer has the capabilities of performing multiple byte reads while
> only asserting the chip select once, rather than reading one register on the
> accelerometer at a time.
>
> The procedure I use for single byte read is the following:
>
> assert Chip Select
> send Read register command //POKE8 -write register address of /
> //ADXL345 to SSP Data Register
> send 8 bits of data //clocks 8 bits of data into SSPDR
> deassert Chip select
> read SSP data register //PEEK8 -read SSPDR
> print to terminal
>
> For multi-byte transmissions I follow the same procedure except before
> deasserting the Chip Select, I continue to send 8 bits of data, for each
> register on the ADXL345 I would like to read from (in my case 6 registers, 3
> axis and 2 for each axis).
>
> The problem I am having is I am not sure that I am reading the SSP data
> register at the correct time or if I am even reading the SSP data register at
> all. I see the correct data on the oscilloscope, so I know that I am
> communicating with the ADXL345 properly and that it is functioning properly.
> However, when I read the SSP data register after each time I send the 8 dummy
> bits meaning new data has shifted into the RX FIFO, I don't read what I see
> on the scope.
>
> I am using some of the source code provided by TS in the FTP repository
> called tempsensor.c and use the POKEXX and PEEKXX functions to write and read
> to/from the SSP data register. Because I have to open /dev/mem to perform
> those POKE and PEEk functions I think something isn't working properly with
> the way I am reading the SSP data register.
>
> How do I know when the end of transmission has occurred? How do I know that
> after I have sent out the 8 dummy bits to shift in new data that the data is
> actually in the SSP register and is ready to be read?
>
> Can anyone please help me???????? I am working on a school project and have
> very limited time to get this done. Anything would help, thank you in
> advance!!
>
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