ADuCM310 Hardware Reference Manual
UG-549
Rev. C | Page 39 of 192
IDACs: Common Use Cases
Case 1: Setting the Output Current of IDAC1 to Quarter Scale
Set up IDAC1CON as follows:
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IDAC1CON[7] = 1: enable writes to the IDAC1DAT register.
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IDAC1CON[0] = 0: power up IDAC1.
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IDAC1CON[5:2] as per Table 26 to set up the filter bandwidth as required.
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IDAC1CON[1] = 0: disable the IDAC1 pull-down current source.
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IDAC1DAT[1] = 0: clear the IDAC1 sync bit to allow immediate updating of the IDAC.
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IDAC1CON[6] = 0: disable the overtemperature shutdown feature.
Set up IDAC1DAT to give a quarter-scale current output.
To calculate the correct value to write to IDAC1DAT, take the following steps:
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Correction tables are provided in flash with error correction values for IDAC1.
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As described in the IDAC Data Register section, appropriate reads from each of the lookup tables for IDAC1 are required to adjust
for nonlinearity errors in each of the four subsections of IDAC1.
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Adjust the corrected value into the format required to load IDAC1DAT.
Case 2: Switch the SOA IDAC from Sourcing Current to Sinking 40 mA
Set up the IDAC6CON register (SOA current sink control register):
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IDAC6CON[7] = 1: enable writes to the IDAC6DAT register.
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IDAC6CON[0] = 0: power up SOA sink current source.
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HVCON[1] = 0: switch on the SOA sink current on the high voltage die.
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Ensure that HVCON[11] = 0 to avoid a negative voltage undershoot when the shutdown is enabled.
Set up the IDAC3CON register:
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IDAC3CON[1:0] = [11] to disable the SOA current source.
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IDAC3DAT[5] = 0: clear the IDAC3 sync bit to allow immediate updating of the IDAC.
Set up the current sink value:
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Set the 11-bit IDAC to midscale (40 mA) by writing IDAC6DAT[27:17] = 0x800.
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Set the IDAC3 to zero scale by writing IDAC3DAT[27:12] = 0x0000. This sets the current source to 0 mA.
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Set HVCON[11] = 1 to pull the shutdown voltage to the lowest trimmed value.
Case 3: Turn On IDAC2 and Set the Output to 0 mA with the Lowest Possible Offset
Set up the IDAC2CON register:
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IDAC2CON[7] = 1: enable writes to the IDAC2DAT register.
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IDAC2CON[0] = 0: power up IDAC2.
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IDAC2CON[5:2] as per Table 26 to set up the filter bandwidth as required.
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IDAC2CON[1] = 0: enable the IDAC2 pull-down current source.
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IDAC2CON[6] = 0: disable the overtemperature shutdown feature.
Set up the IDAC2DAT register:
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IDAC2DAT[27:12] = 0x0000: set the IDAC to zero scale.
Case 4: Set Up All Six IDACs with their Output Current Updating Simultaneously
Set up the IDACs as per previous cases, except this time set IDACx_SYNC[x] = 1 in each of the IDACxDAT registers.
After writing to the last IDACxDAT and IDACxCON register, set IDAC1DAT[5:0] = [000000]b.
This ensures that all six of the current source IDACs are updated at the same time.
