42 lines
1.1 KiB
Plaintext
42 lines
1.1 KiB
Plaintext
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SdFat is setup to use these pins on Teensy 3.0:
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11 - MOSI
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12 - MISO
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13 - SCK
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The following are the SPI bus speeds for
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bool SdFat::begin(uint8_t chipSelectPin, uint8_t spiRate);
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The higher speed is for F_BUS == 48 MHz and lower speed is for F_BUS == 24 MHz.
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spiRate = 0 or 1 : 24 or 12 Mbit/sec
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spiRate = 2 or 3 : 12 or 6 Mbit/sec
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spiRate = 4 or 5 : 6 or 3 Mbit/sec
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spiRate = 6 or 7 : 3 or 1.5 Mbit/sec
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spiRate = 8 or 9 : 1.5 or 0.75 Mbit/sec
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spiRate = 10 or 11 : 250 kbit/sec
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spiRate = 12 or greater : 125 kbit/sec
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Large reads and writes use fast multi-block SD read/write commands. For optimal
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speed, use records that are a multiple of 512 bytes.
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Run the bench.ino example to explore large read/write speed.
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Replace this line:
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#define BUF_SIZE 100
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With a large size like this:
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#define BUF_SIZE 4096
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For best results the record size should be a power of two (512, 1024, 2048,
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4096, 8192). In this case records will be aligned with FAT cluster boundaries.
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Since Teensy is fast, increase the test file size by editing this line:
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#define FILE_SIZE_MB 5
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Run the PrintBenchmark.ino example to compare text formatting speed of
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Teensy 3.0 with AVR boards.
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