75 lines
2.6 KiB
C
75 lines
2.6 KiB
C
// intellectual property is bullshit bgdc
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#ifndef TIMDAC_H
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#define TIMDAC_H
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// ============================================================================
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// TIMDAC
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// ----------------------------------------------------------------------------
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//
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// NOTE - estimated CPU utilization - 0.9% at 72 MHz, 12.25us total
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// (5.48us discharge, 2.29us pulse, 2.14us stabilize, 2.29us transfer) across a
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// 1.29ms cycle
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// ============================================================================
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#include <stdbool.h>
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#include <stddef.h>
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#include <inttypes.h>
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#include <stdatomic.h>
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#include <signal.h>
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#include "timdac_ll.h"
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#define TIMDAC_SCANNER_MAX_CHANNELS 32
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// timdac_scanner provides a higher level interface to timdac, allowing the
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// user to simply write output values as they need changing. When in use, it
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// takes full ownership of the timdac; you should never call any timdac_
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// functions including timdac_init().
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typedef struct timdac_s {
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// #### BEGIN - USER MUST INITIALIZE ####
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// Pointer to the timdac low-level instance in use
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timdac_ll_t * td;
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// Array of output channel values
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atomic_uint * channels;
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// Number of channels, must be no more than TIMDAC_SCANNER_MAX_CHANNELS
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uint8_t n_channels;
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// #### END - USER MUST INITIALIZE ####
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sig_atomic_t volatile chan; // Current channel number
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sig_atomic_t volatile count; // How many channels have been emitted since tuning
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atomic_uint pend; // A pending immediate-update channel
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} timdac_t;
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// Initialize the DAC and DAC scanner. You must have filled in the "USER MUST
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// INITIALIZE" fields in the struct.
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void timdac_init(timdac_t * tds);
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// Start the scanner, if using interrupts. If you are not using interrupts,
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// simply poll in a loop when you want to run - do not call this.
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void timdac_start(timdac_t * tds);
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// Set a new value for an output channel. If no other channel has a pending
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// immediate update, this channel will also be added to the pend slot so that
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// it can be updated as soon as the DAC is ready without waiting for a full
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// cycle.
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//
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// Returns true on success. Only fails on an invalid channel number.
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bool timdac_set(timdac_t * tds, uint8_t chan, int32_t value);
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// Return whether an update is currently pending. Only one channel can hold the
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// pending slot at a time, so if you post an update while another channel is
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// pending, the newer update will not be written to the output until it is
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// next hit in the normal scanning cycle. To ensure the fastest update, you
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// can poll for this flag to clear before calling timdac_set().
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bool timdac_pending(timdac_t * tds);
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// Poll the scanner. Should be called periodically.
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void timdac_poll(timdac_t * tds);
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#endif // !defined(TIMDAC_H)
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