User Manual

Contents Type Size(Bytes) Value Address
Product name string 13 Zmod
DAC () 1411 0x8034
Product model / Part number string 13 Zmod
DAC () 1411 0x8041
Product version / revision string 1 C 0x804E
Serial number string 12 210397000000 0x804F
The analog circuitry described in previous chapters includes passive and active electronic components. The datasheet specs show
parameters (resistance, capacitance, offsets, bias currents, etc.) as typical values and tolerances. The equations in previous chapters
consider typical values. Component tolerances affect DC and AC performances of the Zmod
DAC (). To minimize these effects, the
design uses:
0.1% resistors and 1% capacitors in all the critical analog signal paths
Capacitive trimmers for balancing the Scope Input Divider and Gain Selection
No other mechanical trimmers (as these are big, expensive, unreliable and affected by vibrations, aging, and temperature drifts)
Software calibration, at manufacturing
User software calibration, as an option
A software calibration is performed on each device as a part of the manufacturing test. The AWG outputs are connected to calibrated
voltmeters. A set of measurements is used to identify all the DC errors (Gain, Offset) of each analog stage. Correction (Calibration)
parameters are computed and stored in the Calibration Memory, on the Zmod
DAC () device, both as Factory Calibration Data and User
Calibration Data. The WaveForms software allows the user performing an in-house calibration and overwrite the User Calibration Data.
Returning to Factory Calibration is always possible.
The Software reads the calibration parameters from the Zmod
DAC () MCU via the I2C bus and uses them to correct the generated
signals. The structure of the data is shown below:
Table 3. The Calibration Data Structure []
Heading 1
Name Size
(Bytes) Type
Flash Address (Factory
Calibration)
EEPROM () Address (User
Calibration)
Magic ID 1 uchar 0xAD 0x8100 0x7000
Calibration Time 4 unix
timestamp
0x8104 0x7004
Channel 1 LG
Gain
CG 4 float32 0x8108 0x7008
Channel 1 LG
Offset
CA 4 float32 0x810C 0x700C
Channel 1 HG
Gain
CG 4 float32 0x8110 0x7010
Channel 1 HG
Offset
CA 4 float32 0x8114 0x7014
Channel 2 LG
Gain
CG 4 float32 0x8118 0x7018
Channel 2 LG
Offset
CA 4 float32 0x811C 0x701C
Channel 2 HG
Gain
CG 4 float32 0x8120 0x7020
3.2. Calibration Memory