I have a design using a K60F120 part and an SD card with the esdhc driver.
The driver is configured for a 50 Mhz clock to the sd card, and 4 bit SPI mode. The OS was just updated to to MQX4.2, and MFS is used for the filesystem on the SD card.
I am seeing very slow write speeds to the SD card. FTP writes are roughly 400KBytes/Sec. The MFS swt test utility, when benchmarked with a hardware based millisecond counter I have in the design takes about 32 milliseconds to write each of its 10K files, with performance best at the 512 Byte size.
Has anyone seen similar speeds, and is there a way to speed things up?