MAX1416 Evaluation Kit/ Evaluation System
The Setup, Clock, Offset, and Gain tab sheets provide read/ write access to each of the registers. See Figures
The Comms and Data (Figure 6) tab sheet provides access to the Standby bit. The comms registers RS2, RS1, RS0, and R/W bits are automatically set by each register’s read and write buttons. The channel select bits CH1 and CH0 are determined by which channel is selected on the Measurement tab sheet.
Sampling
To collect data, go to the Measurement tab sheet and click Sample. Select the sample size and click Begin Sampling. After the samples have been collected, the data is automatically uploaded to the host and is graphed. Once displayed, the data can be saved to a file (optional).
Evaluating the MAX1415
To evaluate the MAX1415, request a free sample of the MAX1415EUE and replace U1. Follow the Quick Start procedure, with the following exceptions:
•In step 1, leave JU1 and JU2 open.
•In step 3, apply a +3VDC power supply (instead of +5V) to TB1. Apply an external +1.225VDC differen- tial reference between TB3 pins 3 and 2.
•After step 10, go to the software’s Measurement tab sheet and type the new reference voltage of 1.225 next to REF voltage.
Evaluating the MX7705
To evaluate the MX7705, request a free sample of the MX7705EUE and replace U1. The MX7705 is similar to the MAX1415/1416 except it does not support internal clock mode (INT must always be zero).
Evaluates:
Saving Graphs to Disk
Data in the
Evaluating Power-Down Mode
To enter standby mode, first make sure that Auto Read is not checked in the Measurement tab sheet. Then go to the Comms and Data tab sheet and check power- down, then click write.
Reference Voltage
The evaluation software assumes a 2.500V reference voltage, unless otherwise specified. To override this value, go to the Measurement tab sheet and type the new reference voltage next to REF voltage.
Software Listing
The EV kit software disk contains the driver source and header file. Refer to DRV1416.cpp and DRV1416.h.
Detailed Description
of Hardware
The MAX1416 (U1) is a multichannel,
Using an External Reference
To use an external reference, remove the shunts from JU1 and JU2, and connect a differential reference between TB3 pins 3 and 2. The evaluation software assumes a 2.500V reference voltage, unless otherwise specified. To override this value, go to the Measurement tab sheet and type the new reference voltage next to REF voltage.
Troubleshooting
Problem: No output measurement. System seems to report zero voltage, or fails to make a measurement.
Check VDD supply voltage at TB1. The EV kit requires a separate supply in addition to the supply on the microcontroller module. Check the reference voltage using a digital voltmeter. Use an oscilloscope to verify
that the CS, SCLK, and DIN waveforms are correct. If the DRDY signal is pulsing, then the software has suc-
cessfully initialized the MAX1416 and conversions have been triggered.
Problem: Cannot see MCLK waveform on oscillo- scope.
When using an external crystal, the MCLKIN and MCLKOUT nodes are very sensitive to extra load capacitance. Connecting a typical 10x scope probe effectively doubles the load capacitance from 20pF to 40pF, which can slow down or even halt oscillation. When using the internal oscillator (clock register INT = 1 and CLKDIS = 0), the oscillator signal is visible on the MCLKOUT pin. In this mode, MCLKOUT can be mea- sured using a typical 10x scope probe.
MAX1416/MAX1415/MX7705
_______________________________________________________________________________________ 3
