Bias Current Record; Manufacturing Test - ST STM32L1 Series Application Note

Application description
Low power run / Low power sleep
STOP / STOP without LCD
STANDBY mode
1.5.2

Bias current record

This operation consists of storing the bias current value of operational amplifier A (see
Figure 2) in the data memory. The bias current value is taken into account for low power
measurements in order to minimize measurement errors. Once recorded, this value is kept
in non-volatile memory for later use. It is recommended to perform this operation when you
start your evaluation in order to obtain the best precision.
This mode is only accessible at application power-up by executing the following steps in the
order below:
1. Switch OFF STM32L1xx DISCOVERY
2. Place JP1 in OFF position (I
3. Keep USER push-button pressed while powering ON the STM32L1xx DISCOVERY
4. At power on, a scrolling message "Bias Current" is displayed
5. Release the USER push-button; the bias current value is displayed and immediately
stored in non-volatile memory
Once this operation completed, replace JP1 in ON position so that the measurement
circuitry is connected again to the STM32L152 (I
1.5.3

Manufacturing test

You can access this mode while Demo mode is running, by pressing the USER push-button
for more than 3 seconds and by releasing it. This allows you to verify that the hardware
modules needed by the STM32L1xx DISCOVERY for this example are working properly.
In this mode, application checks the LSE oscillator (Low Speed External), V
value, I
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and upper limits. For each test function, the application displays "OK" and the measured
values when available. If all checks are successfully completed, then the message "TEST
OK" is continuously displayed. If one of the tests fails, then the application alerts the user by
continuously displaying the test name followed by "NO OK".
To exit this manufacturing test, press the RESET button.
Note: Generally, if the manufacturing test is not successful, first check that JP1 is placed in the ON
position and that all solder bridges are in default position. If errors are found in the Low
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Table 1. Bars and LCD display linked to functions (continued)
Function
RUN, OA bias and LP (low power) I
DocID018933 Rev 2
measurement disabled)
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measurement enabled).
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currents. The currents are tested for lower
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AN3413
Bars
voltage
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