60 lines
2.4 KiB
Plaintext
60 lines
2.4 KiB
Plaintext
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This is a demo of a data logging sketch that is capable of logging serial
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data to an SD card at up to 115200 baud.
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You must install the SdFat library to use the SerialPortLogger. SdFat
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can be downloaded from:
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http://code.google.com/p/sdfatlib/downloads/list
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Normally the maximum rate for a 328 Arduino is 57600 baud.
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It is possible to log data at 115200 baud with a 328 Arduino if you use a high
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quality SD card.
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Lower quality cards can have an occasional write latency of over 100
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milliseconds. This will cause a receive data overrun at 115200 baud since
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the RX buffer on a 328 Arduino is 1024 bytes. You need to reduce the baud
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rate to 57600 if your SD card causes receive overruns.
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Most SD cards will work with a Mega Arduino at 115200 baud since the RX
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buffer is set to 4096 bytes.
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It is possible to use software SPI on a Mega by setting MEGA_SOFT_SPI nonzero
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in SdFatConfig.h. This will allow a shield like the Adafruit Data Logging
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shield to be used on a Mega without jumper wires.
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The two programs, SerialPortLogger.ino and SerialDataSource.ino, demonstrate
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high speed logging of serial data.
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To run this demo, you need two Arduino boards and an SD shield or SD module.
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The board with the SD shield should have an LED and series resistor connected
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from pin 3 to ground. This LED will blink an error code if an error occurs.
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Make sure BAUD_RATE has the same value in SerialPortLogger.ino and
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SerialDataSource.ino.
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Load SerialPortLogger.ino into the board with an SD shield or module and
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SerialDataSource.ino into the second board.
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Connect a wire between GND pins on the two boards.
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Connect a wire between the serial RX pin (Pin 0) on the SD board and the
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serial TX pin (pin 1) on the data source board.
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It is best to power the two boards with an external 9V supply.
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After the boards are powered up, wait until the pin 13 LED on the data source
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board goes out. This will take up to 50 seconds.
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Insert an SD into the logger board. press reset on the logger board. The
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error LED connected to pin 3 should not light.
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Press reset on the data source board. The pin 13 LED on the data source
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board should light for about 50 seconds at 57600 baud or 25 seconds at
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115200 baud while 280,000 bytes are transferred.
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If an error occurs, the error LED on the SD board will flash an error code.
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See the SerialPortLogger.ino source for definitions of error codes.
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Remove the SD and check the file SERIAL.BIN. In this case it is a text file.
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