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hardware_specs_and_theory_of_operation [2019/12/20 14:19] turo [Data output] |
hardware_specs_and_theory_of_operation [2019/12/20 14:22] turo [Data output] |
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==== Data output ==== | ==== Data output ==== | ||
- | There are 4 data lines which can either drive two 1-Wire signals or two serial data (Clock+Data) at 5V TTL. | + | There are 4 data lines which can either drive two 1-Wire or two serial data (Clock+Data) signals at 5V TTL. |
If the device is configured for Analog RGB mode some of the data lines are hard-rewired to Power MOSFETs instead of to the internal 5V TTL voltage and can drive up to 6A of power. | If the device is configured for Analog RGB mode some of the data lines are hard-rewired to Power MOSFETs instead of to the internal 5V TTL voltage and can drive up to 6A of power. | ||
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=== Implementation === | === Implementation === | ||
- | The data line are connected to the SPI peripheral pins of the MCU. The MCU does output LED data using DMA+SPI. | + | The data lines are connected to the SPI peripheral pins of the MCU. The MCU does output LED data using DMA+SPI. |
- | The data output pins on the terminals are driven using real 5V TTL. There is a dedicated Linear Regulator which provides 5V, derived from the voltage the DC/DC converter does output. So even with long cables there should be no signal dropout because of a voltage drop. | + | The data output pins on the terminals are driven using real 5V TTL through a MOSFET based level shifter. There is a dedicated linear regulator which provides 5V, derived from the voltage the DC/DC converter does output. So even with long cables there should be no signal dropout because of a voltage drop. |
All data output lines have a 500 Ohm impedance matching resistor in line. This resistor was chosen to handle the most common LED strip setups. In specific cases this 0603 sized resistor might not be appropriate and has to be customized. | All data output lines have a 500 Ohm impedance matching resistor in line. This resistor was chosen to handle the most common LED strip setups. In specific cases this 0603 sized resistor might not be appropriate and has to be customized. |