DAC124S085芯片的使用
该芯片可以通过SPI对其进行操作。具备12bit的能力。
经过实测，该芯片在有基准电源的情况下，输出准确度非常高。
示例代码如下：
1 #include "typedefs.h" 2 3 #define DAC_DAC_A 0b00 4 #define DAC_DAC_B 0b01 5 #define DAC_DAC_C 0b10 6 #define DAC_DAC_D 0b11 7 8 #define DAC_WRITE_SPECIFIC_DO_NOT_UPDATE 0b00 9 #define DAC_WRITE_SPECIFIC_AND_UPDATE 0b01 10 #define DAC_WRITE_ALL_AND_UPDATE 0b10 11 #define DAC_POWER_DOWN 0b11 12 13 /* must give the union some name, otherwise compile error in dcc.*/ 14 struct DAC124S085_REG_tag{ 15 union{ 16 uint16_t R; 17 struct{ 18 uint16_t reg_addr:2; 19 uint16_t action:2; 20 uint16_t raw_value:12; 21 } B; 22 23 } U; 24 };
运行中代码为：
void dac_lld_update(uint8_t which_out, uint8_t which_action, uint16_t voltage_in_mv) { static struct DAC124S085_REG_tag dac_spi_last_command;
uint16_t tmp16;
uint32_t tmp32;
tmp32 = voltage_in_mv*0xFFF;
tmp16 = tmp32/4096; /* 4096 is the ref voltage. */
switch(which_out) { case DAC_DAC_A: // dac_spi_command.U.B.reg_addr = DAC_DAC_A; break; case DAC_DAC_B: dac_spi_command.U.B.reg_addr = DAC_DAC_B; break; case DAC_DAC_C: dac_spi_command.U.B.reg_addr = DAC_DAC_C; break; case DAC_DAC_D: dac_spi_command.U.B.reg_addr = DAC_DAC_D; break; default: return; } switch(which_action) { case DAC_WRITE_SPECIFIC_DO_NOT_UPDATE: dac_spi_command.U.B.action = DAC_WRITE_SPECIFIC_DO_NOT_UPDATE; break; case DAC_WRITE_SPECIFIC_AND_UPDATE: dac_spi_command.U.B.action = DAC_WRITE_SPECIFIC_AND_UPDATE; break; case DAC_WRITE_ALL_AND_UPDATE: dac_spi_command.U.B.action = DAC_WRITE_ALL_AND_UPDATE; break; case DAC_POWER_DOWN: dac_spi_command.U.B.action = DAC_POWER_DOWN; break; default: dac_spi_command.U.B.action = DAC_WRITE_SPECIFIC_AND_UPDATE; } dac_spi_command.U.B.raw_value = tmp16; if(dac_spi_command.U.R != dac_spi_last_command.U.R) { DSPI_Send(1, 0b00000001,dac_spi_command.U.R); /* send spi command */ } dac_spi_last_command.U.R = dac_spi_command.U.R; }
注：
1、适用于参考电压为4096v的情况。
2、SPI代码本文未提供。具体参数见该dac芯片的手册和主控芯片的参考手册。