Quick Start

Before you begin, the following equipment is needed:

• MAX1234EVC16 (contains MAX1234 EV kit board

and 68HC16MODULE-DIP)

• A small DC power supply, such as a 12VDC 0.25A

plug-in transformer, or a 9V battery

• An IBM PC-compatible computer running Windows

95/98/2000

• A spare serial communications port, preferably a 9-

pin plug

• A serial cable to connect the computer’s serial port

to the 68HC16MODULE-DIP

• Standard 4-wire resistive touch screen.

Do not turn on the power until all connections are

made:

1) Ensure that the MAX1234 EV kit’s JU1 jumper has a

shunt installed in the MAX1234 position.

2) Carefully connect the boards by aligning the 40-pin

header of the MAX1234 EV kit with the 40-pin con-

nector of the 68HC16MODULE-DIP module. Gently

press them together. The two boards should be

flush against one another.

3) Connect a 7VDC to 20VDC power source to the µC

module at the terminal block 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 is 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 EV software on your computer by running

the INSTALL.EXE program on the floppy disk. The

program files are copied and icons are created for

them in the Windows Start menu.

6) Turn on the power supply.

7) Start the MAX1234 program by opening its icon in

the Start menu.

8) At the prompt, connect the µC module and turn on

its power. Slide SW1 to the ON position. Select the

correct serial port, and click OK. The program auto-

matically downloads its software to the module.

9) Connect the 4-wire resistive touch screen to the X+,

Y+, X-, and Y- pins of the header. For convenience,

a 20-pin 0.5mm flex cable breakout is provided by

headers H5 and H6.

10) Click Demo Touchscreen. The software tracks the

motion of a stylus on the touch screen (see Figure 1).

11) Click Demo Keypad. The software tracks key

presses (see Figure 5).

Detailed Description

of Software

The EV software’s main window configures the interrupt

handler and displays the internal registers in binary.

To aid development of custom interrupt-driven soft-

ware, the Interrupt Handler tab (see Figure 1) handles

interrupt request (IRQ) response. Both

PENIRQ and

KEYIRQ can be polled, and a set of checkboxes select

the desired response.

The low-level registers are grouped by function. The

ADC regs tab (see Figure 2) controls the analog-to-dig-

ital converter, including the touch-screen digitizer. The

DAC regs tab controls the digital-to-analog output. The

KEY regs tab is for the keypad, and the GPIO regs tab

is for the general-purpose input/output (GPIO) pins.

Each register can be read or written by clicking the cor-

responding Read or Write button. (Registers that can-

not be written do not have a write button.)

The ADC, DAC, KEY, and GPIO buttons open an appli-

cation-oriented view of their respective functions.

Interrupt response is also handled by the main screen.

Analog-to-Digital Converter Window

The MAX1234: Analog to Digital Converter window con-

trols the touch-screen digitizer, the auxiliary voltage

inputs, the temperature measurement, and the refer-

ence voltage. By default, the software automatically

waits for BUSY and then reads updated data after writ-

ing to the ADC control register (see Figure 3).

For improved accuracy, measure the reference voltage

and enter its value into Actual REF Voltage. This only

affects the BAT1, BAT2, AUX1, AUX2, and temperature

voltage reporting. The MAX1234 code outputs are not

affected. When the REFV control bit is changed, the soft-

ware automatically resets the Actual REF Voltage to 1.0V

or 2.5V, unless Ask before changing REF is checked.

The temperature measurement can be further calibrat-

ed by adjusting Room Temperature centigrade and

“TEMP1 Vroom” for TEMP1 measurements, or by

adjusting “Temp2-Temp1 K/delta V” for Temp2-Temp1

measurements. Refer to the MAX1234 data sheet for

more information on temperature measurement.

MAX1234 Evaluation System/Evaluation Kit

2

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