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Evaluates: MAX31343

MAX31343 Shield

Detailed Description

The MAX31343 shield is a low-cost, extremely accurate

RTC. It is driven by an internal temperature-compensated

microelectromechanical systems (MEMS) resonator. The

oscillator provides a stable and accurate reference clock

and maintains the RTC to within ±0.432 seconds-per-

day accuracy from -40°C to +85°C. The RTC device is

The RTC maintains seconds, minutes, hours, day, date,

month, year, and century information. The date at the end

of the month is automatically adjusted for months with

fewer than 31 days, including corrections for leap year

up to the year 2199. The clock operates in the 24-hour

format. Other features including two programmable time-

of-day alarms, interrupt output, uncompensated pro-

grammable clock output, and temperature-compensated

programmable square-wave output. A voltage reference

and comparator circuit monitor the status of VCC to detect

power failures and automatically switch to the backup

supply when necessary.

Detailed Description of Software and

Functional Test Procedure

Real Time Monitoring

To monitor the time and date, on the

Configuration &

Time tab, in the RTC Configuration group box, enable

the

Oscillator Enable toggle button, and in the Real

Time Monitoring group box, check the Continuous

Read checkbox for continuous reading.

Current Draw in Timekeeping Mode

To measure the current draw under normal RTC condi-

tions without any interrupt or CLKO output:

1) Remove the jumper from JU5.

2) With the output set to +3.3V and disabled, connect

the negative terminal of the pico ammeter to the pin

1 of JU5 (marked as a white dot) and the positive

terminal to pin 2 of JU5.

3) On the

Configuration & Time tab, in the Date/Time

Configuration group box, click the Read button.

In the

RTC Configuration group box, disable the

CLKOUT toggle button, and select 1Hz in SQW Fre-

quency drop-down list. In the Real Time Monitoring

section, uncheck the

Continuous Read checkbox.

4) The reading on the pico ammeter is the current

consumed by the MAX31343 IC only. It should be

around 940nA.

CLKOUT Frequency

On the

Configuration & Time tab of the software, in

the

RTC Configuration group box, enable the CLKOUT

toggle button and select the desired frequency. The clock

output can be monitored using an oscilloscope connected

to the CLKO test point (TP7). A frequency counter can

also be used to measure the clock frequency accurately.

Alarm and Timer Configuration

Use the

Alarm & Timer Configuration tab to configure

Alarm 1, Alarm 2, and timer. (Figure 3)