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6: Technical Specifications
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SPI
The Flame has the ability to function as a SPI master through the SPI port, which comprises the
SPI Master Clock, SPI Master MOSI, SPI Master CS, and SPI Master MISO pins. To send
messages over the SPI port, use the
General SPI Input/Output
message. The Flame does not
send or receive any SPI data without direction from its host PC.
Because SPI is a full-duplex transaction, the
General SPI Input/Output
message both reads and
writes at the same time. For instance, a four byte write will return four bytes of dummy read
data, and a four byte read requires four bytes of dummy write data:
MOSI data is established just prior to the rising edge of the SPI clock
MISO data is sampled just after a falling edge of the SPI clock.
I2C
The Flame has the ability to function as an I2C master through the I2C port, which comprises
the I2C-SDA, and I2C-SCL pins. To send messages over the I2C port, use the General I2C
Write and General I2C Read messages. Note that the Flame does not send or receive any I2C
data without direction from its host PC. The I2C lines are pulled up internally to 3.3V by 2K
resistors.
CCD Overview
CCD Detector
The detector used for the Flame is a charge transfer device (CCD) that has a fixed well depth
(capacitor) associated with each photodetector (pixel).
Charge transfer, reset and readout initiation begin with the integration time clock going HIGH.
At this point, the remaining charge in the detector wells is transferred to a shift register for
serial transfer. This process is how the array is read.
The reset function recharges the photodetector wells to their full potential and allows for nearly
continuous integration of the light energy during the integration time, while the data is read out
through serial shift registers. At the end of an integration period, the process is repeated.
When a well is fully depleted by leakage through the back-biased photodetector, the detector is
considered saturated and provides the maximum output level. The CCD is a depletion device
and thus the output signal is inversely proportional to the input photons. The electronics in the
Flame invert and amplify this electrical signal.
Summary of Contents for Flame-S
Page 18: ...1 Introduction 8 225 00000 000 11 201604...
Page 32: ...2 Installation and Setup 22 225 00000 000 11 201604...
Page 46: ...4 Troubleshooting 36 225 00000 000 11 201604...
Page 54: ...5 How the Flame Spectrometer Works 44 225 00000 000 11 201604...
Page 74: ...7 Calibration 64 225 00000 000 11 201604...
Page 130: ...Index 120 225 00000 000 11 201604...