mimxrt: SPI: Set the TCR value returned by MasterBaudSetRate #4474
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without this, the baud rate could be wrong; in my testing, it was low by a factor of 2 when requesating baudrate=1_000_000 (1MHz). When passing the baudrate in to LPSPI_MasterInit, the setting is made automatically, but LPSPI_MAster_SetBaudRate just returns it via the out-parameter tcrPrescaleValue.
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can you test, whats the max SPI clock rate? |
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The SPI clock itself will go fast, here's 30MHz: but the gap between bytes gets relatively longer and longer at higher baud rates, limiting the effective throughput: |
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without this, the baud rate could be wrong; in my testing, it was low by a factor of 2 when requesating baudrate=1_000_000 (1MHz).
When passing the baudrate in to LPSPI_MasterInit, the setting is made automatically, but LPSPI_MAster_SetBaudRate just returns it via the out-parameter tcrPrescaleValue.
This is related to #3062 but is not a solution for it, as there remain long inter-byte gaps.
Now with correct 1MHz SCK rate, but still with multi-microsecond gaps between bytes:
