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56 lines
1.7 KiB
56 lines
1.7 KiB
# Digital Output
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- Direct output access to one or more pins of a port.
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- All selected pins are written simultaneously.
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- Supports generating output pulses of a precise length.
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Pins are ordered in a descending order (DOWNTO) and described in a packed format,
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e.g. if pins 1 and 4 are selected (`0b10010` on the port), the control word has
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two bits `(4)(1)` and e.g. `0b10` means pin 4, `0b11` both. This makes accessing
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the block of pins easier, e.g. when using them to drive a parallel bus. For single-pin units, the control word is always `1`.
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## Commands
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### WRITE (0)
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Write a value to all defined pins.
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*Request:*
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- u16 - new value (packed)
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### SET (1)
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Set pins high
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*Request:*
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- u16 - pins to set high (packed)
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### CLEAR (2)
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Set pins low
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*Request:*
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- u16 - pins to set low (packed)
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### TOGGLE (3)
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Toggle selected pins (high - low)
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*Request:*
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- u16 - pins to toggle (packed)
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### PULSE (4)
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Send a pulse.
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The start will be aligned to 1 us or 1 ms (based on pulse length) of the internal timebase to ensure the highest length precision. This alignment reduces jitter in the pulse duration. A jitter of the pulse start time is less significant, as there's already some unpredictable delay caused by the USB connection and the PC OS scheduler.
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*Request:*
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- u16 - pins to generate the pulse on (packed)
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- u8 - pulse active level (0, 1)
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- u8 - range (0 - milliseconds, 1 - microseconds)
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- u16 - duration in the selected range
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*NOTE:* The microsecond range supports durations only up to 999 us, higher
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numbers will be divided by 1000 and use the millisecond range instead.
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An ongoing pulse is stopped by any command affecting the pin.
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## Events
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*No events defined for this unit type.*
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