102 lines
3.7 KiB
C
102 lines
3.7 KiB
C
/* Arduino WaveHC Library
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* Copyright (C) 2009 by William Greiman
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*
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* This file is part of the Arduino WaveHC Library
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*
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* This Library is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This Library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with the Arduino WaveHC Library. If not, see
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* <http://www.gnu.org/licenses/>.
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*/
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/**
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* Macros and inline functions for MCP4921 DAC
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*/
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#ifndef mcpDac_h
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#define mcpDac_h
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#include <WavePinDefs.h>
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#include <avr/io.h>
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//------------------------------------------------------------------------------
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#define mcpDacCsLow() MCP_DAC_CS_PORT &= ~_BV(MCP_DAC_CS_BIT)
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#define mcpDacCsHigh() MCP_DAC_CS_PORT |= _BV(MCP_DAC_CS_BIT)
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#define mcpDacSckLow() MCP_DAC_SCK_PORT &= ~_BV(MCP_DAC_SCK_BIT)
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#define mcpDacSckHigh() MCP_DAC_SCK_PORT |= _BV(MCP_DAC_SCK_BIT)
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#define mcpDacSckPulse() \
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{ \
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mcpDacSckHigh(); \
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mcpDacSckLow(); \
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}
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#define mcpDacSdiLow() MCP_DAC_SDI_PORT &= ~_BV(MCP_DAC_SDI_BIT)
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#define mcpDacSdiHigh() MCP_DAC_SDI_PORT |= _BV(MCP_DAC_SDI_BIT)
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#define mcpDacSdiSet(v) \
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if (v) { \
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mcpDacSdiHigh(); \
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} else { \
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mcpDacSdiLow(); \
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}
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// send bit b of d
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#define mcpDacSendBit(d, b) \
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{ \
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mcpDacSdiSet(d &_BV(b)); \
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mcpDacSckPulse(); \
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}
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//------------------------------------------------------------------------------
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// init dac I/O ports
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inline void mcpDacInit(void) {
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// set all to output mode
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MCP_DAC_CS_DDR |= _BV(MCP_DAC_CS_BIT);
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MCP_DAC_SCK_DDR |= _BV(MCP_DAC_SCK_BIT);
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MCP_DAC_SDI_DDR |= _BV(MCP_DAC_SDI_BIT);
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// chip select high
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mcpDacCsHigh();
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#if USE_MCP_DAC_LDAC
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// LDAC low always - use unbuffered mode
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MCP_DAC_LDAC_DDR |= _BV(MCP_DAC_LDAC_BIT);
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MCP_DAC_LDAC_PORT &= ~_BV(MCP_DAC_LDAC_BIT);
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#endif // USE_MCP_DAC_LDAC
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}
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//------------------------------------------------------------------------------
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// send 12 bits to dac
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// trusted compiler to optimize and it does
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// csLow to csHigh takes 8 - 9 usec on a 16 MHz Arduino
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inline void mcpDacSend(uint16_t data) {
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mcpDacCsLow();
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// send DAC config bits
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mcpDacSdiLow();
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mcpDacSckPulse(); // DAC A
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mcpDacSckPulse(); // unbuffered
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mcpDacSdiHigh();
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mcpDacSckPulse(); // 1X gain
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mcpDacSckPulse(); // no SHDN
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// send 12 data bits
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mcpDacSendBit(data, 11);
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mcpDacSendBit(data, 10);
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mcpDacSendBit(data, 9);
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mcpDacSendBit(data, 8);
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mcpDacSendBit(data, 7);
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mcpDacSendBit(data, 6);
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mcpDacSendBit(data, 5);
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mcpDacSendBit(data, 4);
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mcpDacSendBit(data, 3);
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mcpDacSendBit(data, 2);
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mcpDacSendBit(data, 1);
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mcpDacSendBit(data, 0);
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mcpDacCsHigh();
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}
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#endif // mcpDac_h
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