Execution Time for the FS_Write() Function in the emFile Library - KBA89381 | Cypress Semiconductor
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Execution Time for the FS_Write() Function in the emFile Library - KBA89381
Why does the FS_Write() function in the emFile library vary in its execution time?
If the SD card is in a busy state, there will be a delay in responding to FS_Write().
The SD card in SPI mode will always respond to a command from the host, according to section 7.2.8 Error Conditions of the SD Specifications Part 1 Physical Layer Simplified Specification Version 4.10. This means that the function FS_Write() is a blocking function and it waits until it gets a response from the SD card. Hence, the execution time for the FS_Write() function will vary.