SPI Master Interface Bitrate
Hey together,
I have a question regarding the bitrate of the SPI Master Control Port. We have an EEPROM connected to the SPI Master Control Port to store some user data and this works fine. But we noticed that the SPI Clock frequency is always at around 5 MHz (4.8 MHz).
We plan to integrate an EEPROM which supports up to 1 MHz.
- Is there a way to change the SPI clock frequency?
We tried to change it by setting the propertie "Bitrate" of the master control interface, but this has no effect. We can only change it by changing the main PLL frequency.
Best regards,
Eric
Audio Signal Processors
adau1452
software
spi
SigmaDSP Audio Processors
Sigma Studio v4.7
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Hello Eric,
Thanks for reporting this.
It seems like, the SPI config window of SPI read module doesn't update the clock speed if we input below 5MHz (700KHz, 1MHz, 2MHz, etc), it just stays at 5MHz (around 4.9MHz) if we input below it.
It works fine above 5MHz. It outputs the clock whatever that we configured in the window above 5MHz.
You can see in the below picture that it works fine with 10MHz and 7MHz.
However, we can work around this by directly updating the value into that particular register.
Below is how we can achieve 1MHz clock speed by overwriting the spi_speed value using parameter update block.
Here is the calculation.
SPI_speed_config_value (32.0 format) = Ceil(SYSCLK/(2*SPI_CLK))
For 1MHz SPI clock,
X = 294.912MHz/2*1MHz = 147.456
I have written this integer to spi speed parameter using a DC block with parameter update module. Now it outputs 1MHz clock.
Hope this helps!
ADAU1467 DLL also has this problem with SPI read module.
The EEPROM window SPI configs are working fine with SPI speed > 400KHz.
Regards,
Harish
Hey Harishgowtham,
this worked, thanks for the fast answer. Not many functions are working correct in the configuration window for the SPI Master Port :). But anyway in the end it seems to work.
Best regards,
Eric
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