Hi All
I have an application where I am capturing 4 channels of 24bit Analog at 128ksps.
The T4.1 I am using has 16MBytes of QSPI ram installed and I use this as a buffer for batch mode but intend to use some of it as a circular buffer for a continuous write to SD card if it can be made to write fast enough on average.
Simple testing so far shows that I can get an average write speed (when just writing a batched file from RAM to card) of about 2Mbytes per second.
With the above scheme operating, it looks like I will need 128000 * (4 x 3 (ADC)+ 8 (digital inputs) ) = 2560000 bytes per second so faster than I have observed the SD writes on average to date.
If I trim the ADC results to 16 bit (realistically that's all the resolution this ADC can achieve at that sample rate) then this becomes 128000x (4x2 + 8) = 2048000 bytes per second so might be doable.
Does anyone know if an SD card write on the T4.1 with plain SPI can write this fast on average?
Has anyone tried using one of the QSPI ports to support an SD card interface?
Craig
I have an application where I am capturing 4 channels of 24bit Analog at 128ksps.
The T4.1 I am using has 16MBytes of QSPI ram installed and I use this as a buffer for batch mode but intend to use some of it as a circular buffer for a continuous write to SD card if it can be made to write fast enough on average.
Simple testing so far shows that I can get an average write speed (when just writing a batched file from RAM to card) of about 2Mbytes per second.
With the above scheme operating, it looks like I will need 128000 * (4 x 3 (ADC)+ 8 (digital inputs) ) = 2560000 bytes per second so faster than I have observed the SD writes on average to date.
If I trim the ADC results to 16 bit (realistically that's all the resolution this ADC can achieve at that sample rate) then this becomes 128000x (4x2 + 8) = 2048000 bytes per second so might be doable.
Does anyone know if an SD card write on the T4.1 with plain SPI can write this fast on average?
Has anyone tried using one of the QSPI ports to support an SD card interface?
Craig