Re: [myhdl-list] *** GMX Spamverdacht *** Re: Hello World

[Günther S. <gue...@gm...>]

Are you sure?
This is not a 4-Wire SPI. It is a 3 wire SPI.
For a 4 wire  there are extra ports for reading and writing,
but with 3-wire the SDIO-port has the possibility to set a read or a 
write bit
from the accelerometer wich is described here:
http://www.geeetech.com/Documents/ADXL345%20Datasheet.pdf
And this SDIO-port of the accelerometer is connected with I2C_SDAT of 
the Altera CyclonIV
The problem is, that i do not know wheater i am doing something wrong 
with the
bite sequences, which get into the accelerometer.
So i whould very much appreciate, if someone could
just run the simulation and take a look at the bitsequence in
gtkwave and say if this bit sequence is making sense at all,
or i am doing something really strange here?
Thank you very much.
Regards,
guenther






Am 26.04.2015 um 15:13 schrieb Christopher Felton:
> On 4/26/15 12:06 AM, Günther Stangassinger wrote:
>> Thank you for your quick response.
>> Yes it is the latest board with cyclone-IV
>> No, i am communicating over SPI.
> If you are using SPI you do not need a tristate,
> only I2C requires a tri-state for the SDA bi-direction
> (usually don't need one for SCL).
>
> If you are using SPI I would remove the tristate.
> Make sure the CSn signal goes low, didn't review
> the data sheet fully, don't know if it can be tied
> low or if it needs the transition.
>
> Regards,
> Chris
>
>
>
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