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52 lines
1.4 KiB
52 lines
1.4 KiB
# SIPO - Multi-cast Shift Register Driver
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*SIPO stands for Serial Input Parallel Output*
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- Used for building user interfaces (LED displays etc.)
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- Designed for driving 74xx595 or 74xx4094
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- Can drive multiple data lines in parallel
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- Offers direct pin access without sending data (no clock pulse)
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- Supports data latch on Store pulse (see the WRITE command for details)
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- Pin polarities are configurable in the unit settings.
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The `DIRECT_*` commands are mostly meant for debugging purposes when trying to communicate with an unfamiliar SIPO-based board.
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## Commands
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### WRITE (0)
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Sends data to the shift registers.
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After each byte, the *Shift* pin is pulsed. After the last byte and the *Shift* pulse, the *Latch* data is output followed by the *Store* pin pulse.
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The *Latch* data is normally 0 and doesn't matter; however, it's possible to design
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external circuitry that latches the data pins on the *Store* pulse, e.g. for brightness
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control or extra LEDs.
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*Request:*
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- u16 - latch data to output before the Store pulse - all outputs, packed
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- (u8 array) x num_outputs
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- must be a multiple of the outputs count (if 1, simply the output data)
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### DIRECT_DATA (1)
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Direct write to the data pins, without any pulse.
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*Request:*
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- u16 - data to output, packed
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### DIRECT_CLEAR (2)
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Pulse the *Clear* output.
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### DIRECT_SHIFT (3)
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Pulse the *Shift* output.
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### DIRECT_STORE (4)
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Pulse the *Store* output.
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## Events
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*No events defined for this unit type.*
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