General Description
The MAX1403 evaluation system (EV system) is a com-
plete, multichannel data-acquisition system consisting of
a MAX1403 evaluation kit (EV kit) and a Maxim 68HC11
microcontroller (µC) module. The MAX1403 is a low-
power, multichannel, serial-output analog-to-digital con-
verter (ADC). Windows 95/98TM-compatible software pro-
vides a handy user interface to exercise the MAX1403's
features. Source code in C++ and 68HC11 assembly lan-
guage is provided for the low-level portion of the software.
Order the EV system for comprehensive evaluation of
the MAX1403 using a personal computer. Order only
the EV kit if the 68HC11 µC module has already been
purchased with a previous Maxim EV system or for cus-
tom use in other µC-based systems.
The MAX1403 EV kit and EV system can also be used
to evaluate the MAX1401. Simply order a free sample of
the MAX1401CAI along with the MAX1403EVKIT.
MAX1403 Stand-Alone EV Kit
The MAX1403 EV kit provides a proven PC board layout
to facilitate evaluation of the MAX1403 with user-provid-
ed software and hardware. It must be interfaced to
appropriate timing signals for proper operation. Refer to
the MAX1403 data sheet for timing requirements. See
Table 2 for jumper functions.
MAX1403 EV System
The MAX1403 EV system operates from a user-sup-
plied +5V to +12V DC power supply.
Features
o
Easy to Configure
o
Collects Up to 8192 Samples at Full Speed
o
Complete Evaluation System
o
Proven PC Board Layout
o
Fully Assembled and Tested
Evaluates: MAX1401/MAX1403
MAX1403 EV System
________________________________________________________________
Maxim Integrated Products
1
19-1490; Rev 0; 5/99
MAX1403 EV System
Component List
PART
MAX1403EVKIT
MAX1403EVL11
0°C to +70°C
0°C to +70°C
TEMP. RANGE
INTERFACE TYPE
User-Supplied
Windows Software
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
Ordering Information
Component Suppliers
MAX1403 EV Kit
Component List
Not installed
0
R10
Not installed
0
R9
10
, 5% resistors (1206)
2
R7, R8
100
, 5% resistors (1206)
6
R1R6
Not installed
0
JU1JU8
Female SMA connector
1
J2
DESIGNATION
2 x 20 right-angle socket
1
J1
2.2µF aluminum electrolytic radial-
leaded capacitor
1
C15
Not installed
0
C12, C13
0.1µF ceramic capacitors (1206)
3
C9, C10, C11
100pF ceramic capacitors (1206)
6
C3C8
DESCRIPTION
QTY
Windows 95/98 is a trademark of Microsoft Corp.
Note:
The MAX1403 software can be used only with the com-
plete evaluation system (MAX1403EVL11), which includes the
68L11DMODULE together with the MAX1403EVKIT.
PART
68HC11 µC Module
1
68L11DMODULE
MAX1403 Evaluation Kit
1
MAX1403EVKIT
DESCRIPTION
QTY
Maxim MAX1403CAI
1
U1
Maxim MAX6520EUR
(SOT23 voltage reference, 1.2V,
20ppm/°C max)
1
U2
2.4576MHz ceramic resonator
Murata CST2.45MGW040
1
Y1
3" x 4" PC board
MAX1403 evaluation kit
1
None
3 1/2" software disk
MAX1403 evaluation kit
1
None
Maxim 68HC11 module monitor, ROM
Version 1.1 (Version 1.0 ROM will not
work with this EV kit.)
1
None
Evaluates: MAX1401/MAX1403
MAX1403 EV System
2
_______________________________________________________________________________________
_________________________Quick Start
Recommended Equipment
Obtain the following equipment before you begin:
· A DC power supply that generates +5VDC to +12VDC
at 30mA to 50mA
· An IBM PC-compatible computer running Windows
95/98
· A spare serial communications port, preferably a 9-
pin plug
· A serial cable to connect the computer's serial port
to the Maxim 68HC11 Module
1) Before you begin, make sure your 68HC11 module
has the Rev. 1.1 ROM. The software will not function
with the Rev. 1.0 ROM.
2) Carefully connect the boards by aligning the 40-pin
header of the MAX1403 EV kit with the 40-pin con-
nector of the 68HC11 module. Gently press them
together. The two boards should be flush against
one another.
3) Connect the DC power source to the µC module at
terminal block J2, located next to the ON/OFF
switch, along the top edge of the µC module.
Observe the polarity marked on the board.
4) Connect a cable from the computer's serial port to
the µC module. If using a 9-pin serial port, use a
straight-through, 9-pin female-to-male cable. If the
only available serial port uses a 25-pin connector, a
standard 25-pin to 9-pin adapter will be required.
The EV kit software checks the modem status lines
(CTS, DSR, DCD) to confirm that the correct port
has been selected.
5) Install the software on your computer by running the
INSTALL.EXE program from the floppy disk. The
program files are copied and icons are created for
them in the Windows 95/98 Start Menu. The EV kit
software evaluates both the MAX1403 and the
MAX1401.
6) Start the MAX1403 program by opening its icon in
the Start Menu.
7) The program will prompt you to connect the µC
module and turn its power on. Slide SW1 to the "ON"
position. Select the correct serial port, and click OK.
The program will automatically download the file
KIT1403.L11 to the module.
Example Source Code Files
68HC16 Source Code Files
Install/Uninstall Program Files
Header file for MAX1403.CPP, provided for
reference.
MAX1403.H
DESCRIPTION
FILE
Source code defining the program inter-
face with the Maxim 68HC11 Module ROM
(Rev. 1.1).
EVKIT.ASM
Main source code for the KIT1403.L11 pro-
gram, provided for reference. Maxim holds
the copyright but allows customers to
adapt the program for their own use without
charge.
KIT1403.ASM
Database for uninstall program.
UNINST.INI
Installs the EV kit files on your computer.
INSTALL.EXE
Removes the EV kit files from your comput-
er. This file is automatically copied to
C:\WINDOWS during installation.
UNMAXIM.EXE
MAX1403 EV Kit Files
Windows Application Program Files
Program settings file
MAX1403.INI
Software loaded into 68HC11 microcon-
troller
KIT1403.L11
Help file
MAX1403.HLP
Application program that runs under
Windows 95/98
MAX1403.EXE
DESCRIPTION
FILE
DESCRIPTION
FILE
DESCRIPTION
FILE
Source code module for driving the
MAX1403, provided for reference. Includes
definitions of the register names and low-
level access routines. Compiled with
Borland C++ 4.52. Maxim holds the copy-
right but allows customers to adapt the pro-
gram for their own use without charge.
MAX1403.CPP
8) When the software successfully establishes commu-
nication with the EV kit board, you will see a configu-
ration tool and some other windows. Verify that the
CLKIN and Reference Voltage settings are correct.
Close or minimize this dialog box.
9) Apply input signals to the inputs labeled AIN1AIN5,
at the bottom edge of the MAX1403 EV kit board.
AIN6 is analog common. Observe the readout on
the screen.
Upgrading the 68HC11 Module
The MAX1403 EV kit requires Rev. 1.1 of the Maxim
68HC11 Module ROM. Check the label on device U10
on the module; if it says "Rev. 1.0," the device must be
replaced.
The Rev. 1.1 ROM is a 28-pin DIP that comes with the
EV kit. If it was omitted, contact the factory for a
replacement.
To install the new ROM, use the following procedure.
Use antistatic handling precautions. To reduce the risk
of ESD damage, gather all required materials and per-
form the installation at one sitting.
1) Slide the ON/OFF switch to the OFF position.
2) Using a flat-blade screwdriver, gently pry U10, the
REV 1.0 ROM, out of its socket.
3) Remove the REV 1.1 ROM from its antistatic pack-
aging.
4) Align the REV 1.1 ROM in the U10 socket pins.
Observe correct polarity (the notch at the top of the
ROM). Verify that the pins are lined up with the
socket, and gently press the ROM into place.
Proceed to the regular
Quick Start instructions.
Detailed Description
_________________________of Software
The MAX1403 digitizes up to seven inputs. The various
program functions are grouped into windows that are
accessible from the Show menu on the main menu bar.
Main Display
The main display shows the calculated input voltage
and raw A/D output code for each active channel.
Although there are nine input channels, only certain
configurations are allowed.
Select any single channel or one of the scanning
sequences from the Inputs menu. AIN 1-6 designates
an analog input between the AIN1 pin and the AIN6 pin.
CALOFF designates the signal between the CALOFF+
and CALOFF- pins. CALGAIN designates the signal
between the CALGAIN+ and CALGAIN- pins.
The EV kit software assumes that CALOFF+ and
CALOFF- are grounded so that CALOFF measures 0V.
Similarly, the software assumes that CALGAIN+ is con-
nected to REFIN+ and CALGAIN- is connected to
REFIN- so that CALGAIN measures the reference volt-
age. These two points calibrate the code-to-voltage
translation function performed in the software.
The MAX1403 automatically triggers its measurements,
unless the FSYNC control bit is set. The EV kit software
communicates with the MAX1403 at intervals deter-
mined by the Update Every combo box. To halt this
automatic update, uncheck the Update Every checkbox
or change the Update Every to a value between 100ms
and 60,000ms.
Normally, the microcontroller collects new data as soon
as it becomes available by using the INT pin to trigger
an interrupt service routine. If the INT pin is not used as
an interrupt, then the MAX1403 must not be operated in
free-running mode. Check or uncheck the Use INT
Interrupt checkbox to configure the evaluation kit soft-
ware.
Configuration Tool
The Configuration Tool controls parameters that apply
to the entire EV kit. Like the other windows, the
Configuration Tool can be activated from the Show
menu of the main menu bar. The CLK control should
match the external ceramic resonator or crystal that
sets the master clock frequency. The VREF Reference
Voltage control tells the software what the reference
voltage is. This is used to convert the raw A/D output
codes into the corresponding input voltage to speed
user evaluation. The Data-Rate control determines how
often the MAX1403 performs a measurement. Some
data rates provide 16-bit, noise-free resolution when
used with the SINC
3
filter (discussed below). The Filter
Sync control can be used to inhibit the MAX1403 from
performing its self-timed measurements. The Buffer
Inputs checkbox enables the internal input buffers. The
Burnout Test Currents checkbox enables two small
(0.1µA) current sources to provide an input stimulus.
When used with a transducer, these current sources
can be used to verify that the transducer has not failed
open or short circuit.
At the bottom of the window are input voltage-range
selection buttons. These buttons configure all input
channels for the same input voltage range. Although
the MAX1403 can be operated with three different input
ranges at the same time, the EV kit software supports
only a single range for all channels.
Evaluates: MAX1401/MAX1403
MAX1403 EV System
_______________________________________________________________________________________
3
Evaluates: MAX1401/MAX1403
The digital filter on the MAX1403 can be configured for
SINC
3
or SINC
1
operation, which affects the filter cutoff
frequency. (SINC
1
means SIN(X) ÷ X, and SINC
3
means
(SIN(X) ÷ X)
3
.) The SINC
3
filter is required for 16-bit accu-
racy. The SINC
1
filter provides faster settling time with less
accuracy. Alternatively, the raw modulator output can be
driven out the DOUT pin; however, the EV kit software
cannot read data from the MAX1403 in this mode.
Calibration Tool
The MAX1403 EV kit software can average the mea-
surements from the calibration channels and use the
measured values to correct the voltage displays. The
calibration algorithm assumes that the CALOFF inputs
are externally connected together and that the CAL-
GAIN inputs are externally connected to the reference
voltage (VREF). View the calibration tool by selecting it
from the Show menu.
The software automatically disables calibration if either
of the calibration channels reports a code of 0 or
262143. This is to prevent erroneous calibration when
using a transfer function that does not include both 0V
and VREF.
When Use CALOFF and CALGAIN for Calibration is
checked, the software averages the raw A/D codes for
the CALOFF and CALGAIN channels. The average is
calculated as a weighted sum of the new data and the
old average value. The Slower/Faster slide bar controls
the weight of the new data vs. the weight of the old
average.
The EV kit software assumes that all three transfer func-
tion registers are set to the same value.
This calibration affects only the displayed voltage, not
the raw code numbers. The average CALOFF and
CALGAIN code values are used as the endpoints of a
linear interpolation, with CALOFF measuring 0V and
CALGAIN measuring VREF.
The linear interpolation formula is as follows:
Note:
When using the calibration tool with the
MAX1403 in buffered mode, CALOFF+ and CALOFF-
should be disconnected from GND and connected
instead to REFIN+ so that they remain within the speci-
fied input range.
Sampling Tool
To sample data at full speed, select Sample from the
main display menu, make your selections, and click on
the Begin Sampling button. Sampling rate is controlled
by the Configuration tool. Sample size is restricted to a
power of two. Sample Size controls the number of sam-
ples collected on each selected channel. After the
samples have been collected, the data is automatically
uploaded to the host and is graphed. Once displayed,
the data may be saved to a file.
While the Sampling tool is open, the other windows are
locked out. Close the Sampling tool by clicking the
Close icon in the upper corner.
Register Display Tool
This tool displays all of the internal registers of the
MAX1403. Modify any bit value by checking or
unchecking its box. (The START bit and the zero bits in
the Special Function register (SFR) cannot be modi-
fied). The Read All Registers button causes the soft-
ware to read all of the MAX1403's registers. (Not func-
tional when the MDOUT or FULLPD bit is set.) Refer to
Table 1 for a guide to register bit functions.
Communications Register (COMMS)
Setting the FSYNC control bit inhibits the MAX1403
from performing its self-timed measurements. If
FSYNC = 1 when it is time to perform a measurement,
the MAX1403 simply skips that measurement. Thus,
power-line frequency rejection is not affected by the
FSYNC bit.
Setting the STDBY bit places the part in low-power
standby mode. The serial interface and the CLK oscilla-
tor continue to operate. The part can be restored to
normal operation by clearing the STDBY bit.
Special Function Register (SFR)
Setting the MDOUT bit makes the raw modulator output
available on the DOUT pin; however, the EV kit software
cannot read data from the MAX1403 in this mode.
Setting the FULLPD bit in the SFR register places the
part in full power-down mode. The master oscillator
does not run. To restore normal operation, click on the
Reset menu item in the main display. This causes the
68HC11 software to pulse the MAX1403 RESET pin.
Transfer Function Registers (TF1, TF2, TF3)
The three transfer function registers (TF1, TF2, TF3) con-
trol how input voltage is mapped to code values. The
transfer function registers control a programmable-gain
amplifier (PGA) and an offset-correction DAC.
If U/B = 1, the transfer function maps unipolar voltages
between 0V and VREF. If U/B = 0, then the transfer
function maps bipolar voltages between -VREF and
+VREF. Next, the PGA increases the code-per-volt pro-
Voltage
VREF Code CALOFFcode
CALGAINcode CALOFFcode PGAgain
=
-
-
(
)
(
)
MAX1403 EV System
4
_______________________________________________________________________________________
cessing gain, reducing the full-scale voltage range by a
factor of 1, 2, 4, 8, 16, 32, 64, or 128. Finally, the offset-
correction DAC offsets the voltage range by up to ±7/6
of the full-scale voltage range.
Input pins AIN1 and AIN2 are controlled by TF1. Input
pins AIN3 and AIN4 are controlled by TF2. Input pin
AIN5 is controlled by TF3. Input pin AIN6 is the analog
common.
When SCAN = 1, the CALOFF and CALGAIN channels
are controlled by TF3. When SCAN = 0, the CALOFF
and CALGAIN channels are controlled by one of the
transfer function registers, as selected by the A1 and
A0 bits.
For simplicity, the EV kit software assumes that all three
transfer functions are configured alike.
Detailed Description
________________________of Hardware
U1, the MAX1403, is a multichannel, high-resolution
A/D converter (refer to the MAX1403 data sheet). U2,
the MAX6520, is a 1.2V reference (refer to the
MAX6520 data sheet). Y1 contains a ceramic resonator
and its load capacitors. R1R6, together with C3C8,
form anti-aliasing input filters. R8 and C11 filter the digi-
tal power supply. The analog supply comes through fil-
ter R7/C10.
Input Filtering
The EV kit has an RC filter on each input with a time
constant of approximately 0.01µs = 10ns (R = 100
,
C = 100pF). When scanning between channels, the RC
filter's settling time may increase the acquisition time
required for full accuracy.
Evaluating the MAX1401
The MAX1401 can be evaluated by shorting across
jumpers JU6 and JU7. The MAX1401 is exactly like the
MAX1403, except that the function of pins 5, 6, 7, and 8
is changed. Instead of the OUT1/OUT2 outputs and
DS0/DS1 inputs, these pins are used to provide access
to the analog signal between the multiplexer and the
A/D converter. Tables 2 and 3 list the jumper functions
and default settings. Refer to the MAX1401 data sheet
for detailed information.
Measuring Supply Current
Supply current can be estimated by measuring the volt-
age across a series resistor. On the EV kit board, the
MAX1403 draws all of its analog and digital power
through R8, which is 10
. In addition, all analog supply
current flows through R7, which is also 10
.
Troubleshooting
Problem:
unacceptable amounts of noise in the signal.
Collect a sample of 1024 measurements at a 60Hz data
rate. Observe whether the problem is caused by 60Hz
noise.
Any AC-powered equipment connected to the analog
signal ground can inject noise. Try replacing AC-pow-
ered DVMs with battery-powered DVMs.
Evaluates: MAX1401/MAX1403
MAX1403 EV System
_______________________________________________________________________________________
5
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