Use Master SPI and ADUSBEBZ together?
Hi,
we are planning a new product using an ADAU1452 sigmaDSP, which will have an external microcontroller connected via SPI to update the control parameters.
I would also like the option of connecting an ADUSBEBZ interface (as supplied with most of the evaluation boards) to it so that I can use SigmaStudio to load and debug the sigmaDSP in real time.
It seems to me that both require to be connected to the Master Control Port but I can't work out if they would mutually interfere with each other, has anyone tried this? and if so how did you connect them to make it work?
Any comments gratefully received
PhilipJ
Audio Signal Processors
adau1452
SigmaDSP Audio Processors
Hi Philip,
You wouldn't need to have either connected to the Master Control Port -- there is a different set of slave SPI/I2C pins for the ADAU1452, which is what you should be using instead for the ADUSBEBZ and your micocontroller.
The one issue that you will need to address will be the nature of SPI to not be friendly towards multiple masters on one bus. Since the SPI master will be pulling the lines up, you will need to find a workaround -- if your microcontroller will allow you to tristate the SPI lines when not in use, that would work. Alternately, you could install jumpers so that the microcontroller could be disconnected from the SPI bus when the USBi is connected.
Regards,
Tyler
Hi Tyler,
thanks for your fast response. As you suggest, I had thought my solution would be to be able to tell the microcontroller to tri-state it's pins so the ADUSBEBZ can then be plugged in for debugging. I just wondered if any had found a more elegant solution.
I take your point about the other set of pins but I really want to have my CPU work as SPI Master. If I understand the data sheet correctly the other pins are fixed as being SPI Master for booting from EEPROM or controlling peripherals so I can't use them.
Anyway the tri-state approach should work OK
Regards
PhilipJ
Sorry my mistyping, I meant the ADAU1452 Slave port. Also used by the ADUSBEBZ, hence my original query.
regards
PhilipJ
Hi Philip,
If you want your CPU to be the SPI master, then it should not be connected to the ADAU1452 Master Control Port. The Master Control Port exists only for applications where you want the ADAU1452 to be able to update external parameters or initiate a self-boot. If you don't plan to do either of those things (using the ADAU1452 as the master), then you just need to connect MISO, MOSI, SCLK, and SS, which are slave ports.
Regards,
Tyler
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