Evaluate: MAX1057/MAX1058/MAX1257/MAX1258
standard 25-pin to 9-pin adapter is required. The
EV kit software checks the modem status lines
(CTS, DSR, and DCD) to confirm that the correct
port has been selected.
7) Start the MAX1258 program by opening its icon in
the Start | Programs menu.
8) Turn on the power supply and slide SW1 to the ON
position on the 68HC16MODULE-DIP module.
Press the OK button to automatically connect and
download the file KIT1258.C16 to the module.
9) Apply an input signal to AIN0 and click Perform
Action. Observe the readout on the screen. To per-
form the action repeatedly, check the every 200ms
checkbox.
10) To view a graph of the measurements, pull down
the View menu and click Graph.
11) Bring up the DAC Outputs tab, select action 1111
cccc cccc 001x Power On Selected Channels,
and click Perform Action.
12) Select action 1100 Write and Load OUT1-OUT8,
set OUT1 code to 2048, and click Perform Action.
Observe that the voltage on OUT1 is now midscale
(2.048V, assuming VREF = 4.096V).
13) Bring up the GPIO Pins tab. Set GPIOA0 to High
Output, set GPIOB0 to Low Output, set GPIOC3 to
Input, and click Write Output Pins. Observe that
the A0 pin is now logic-high and the B0 pin is now
logic-low.
14) Connect GPIO pin C3 to logic-high (A0) and click
Read Input Pins. Observe that the software indi-
cates that C3 is high.
15) Connect GPIO pin C3 to logic low (B0) and click
Read Input Pins. Observe that the software indi-
cates that C3 is low.
Detailed Description of
Software
The main window of the evaluation software configures
the data converter and measures the analog inputs.
Under Action, select a scanning sequence, repetitive
conversions, or a single conversion. Each selected
channel's measurement results are displayed in the
corresponding Measurement Results field.
The Action setting read single channel repeatedly
requires making a selection under Repetition to deter-
mine how many times the selected channel should be
measured.
Use Averaging to summarize a series of measure-
ments results on each selected channel as an arith-
metic mean value. Repetition can be used together
with Averaging to summarize a large number of mea-
surement results as a small number of sample means.
The Low Level Interface Details panel shows the most
recent low-level register write. A summary of what has
been written to each register is available under the
Low-level registers tab.
The AIN14 and AIN15 channels are automatically
skipped if their alternate functions are selected in the
setup register. The evaluation software updates its dis-
play to show or hide these channels whenever the alter-
nate functions are enabled or disabled.
The Setup tab configures the alternate functions for the
AIN14 and AIN15 pins, and also configures adjacent
channels as differential input pairs.
The Low-level registers tab summarizes the com-
mands that create the active configuration. The Reset
All Registers checkbox resets these software-shad-
owed register values and sends the reset command to
the MAX1258, optionally configuring slow mode and
bandgap mode.
DAC Outputs
The DAC Outputs tab in the main window controls the
analog output pins.
To power DAC channels prior to use, select action
1111 cccc cccc 001x Power On Selected Channels.
Verify that the checkboxes are set and click Perform
Action. Jumper JU2 defines the initial states of the
DAC output pins.
To reset all DAC outputs to zero, select action 0001 0...
Reset all DACs to 000 (zero scale) and click Perform
Action.
To reset all DAC outputs to full scale, select action
0001 1... Reset all DACs to FFF (full scale) and click
Perform Action.
Note: At power-on the DAC expects an external refer-
ence on REF1. Refer to the MAX1258 IC data sheet.
To write and load multiple DAC channels, select action
1100 Write and Load OUT1-OUT8, type the desired out-
put code value (0 to 4095) into the OUT1 edit field, and
click Perform Action. The voltage on the OUT1–OUT8
pins immediately changes to the new value.
To write a single DAC output (for example OUT5), select
action 0110 Write OUT5. Type the desired output code
value (0 to 4095) into the OUT5 edit field and click
Perform Action. Unless jumper JU5 is closed (asserting
the LDAC pin low), a separate load command is required
to update the pin voltage from the input register. Load
OUT5 by selecting action 1110 cccc cccc xxxx Load
MAX1258 Evaluation Kit/Evaluation System
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