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SPI

Posted: Mon Oct 15, 2018 10:30 pm
by Din
Hi,

I'm using Astrobe for FPGA RISC5 on ARTY and I'm new to Astrobe and Oberon system. The application i'm working on is IOT based where SPI is used to communicate with WIZNET W5500 (https://www.wiznet.io/product-item/w550 ... et-shield/).

Initially I tested the communication on Firmware (Without operating System) by providing instructions to PROM file. I used SS[1] (I figured SS[0], is dedicated to SD card PMOD). This part was quite easy because i tested on bare metal without any operating system.
Now that i have to move to software, Im concerned about single SPI being used for SD card and Wiznet chip. Im aware of the fact they have 2x MOSI,MISO,SS,SCLK but are there are chances that SPI talking to Wiznet might get interrupted by Operating system ?
Im not very sure if the threads are sequential, how frequently will the SPI be used for SD card. I was also thinking to make another instance of SPI and dedicate it to Wiznet. I would appreciate if you could share your thoughts.


regards,
Dinesh

Re: SPI

Posted: Tue Oct 16, 2018 10:54 am
by cfbsoftware
I don't think it will be a problem. Unless you are actually writing to the SD card yourself it should only be accessed if you are uploading a compiled file from your PC or when a module is loaded for the first time since system startup. After that the module remains resident in RAM unless you explicitly unload it. The only background task that runs is the garbage collector but even that does not interrupt a running command.