AN4460 datasheet(24/54 Pages) STMICROELECTRONICS

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Firmware implementation

AN4460

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DocID026129 Rev 1

which uses two interrupts to read or write characters to the serial line. The serial interrupts

use the lowest priority level among all the other sources (STMR, AWU, SMED and ADC).

5.3

Printf

The STLUX385A firmware implements the standard “printf()” subroutine, which takes

several cycles to expand the printed strings and the operation delay real-time events. It is

suggested the use of “printf” in production code is minimized or removed.

5.4

Low power modes

The STLUX385A may enter low power modes through the instruction WFI (wait for

interrupt), where the internal CPU is stopped until an interrupt is received.

The “wi” console command instruction allows the user to use the WFI instruction (see

Section 7.4.10 on page 33).

The user may implement more aggressive low power schemes via new software routines.

For example, the STLUX385A power consumption efficiency could be increased by

disabling the SMEDs and the 96 MHz PLL while the LED string is completely switched OFF.

AN4460 Datasheet(PDF) 24 Page - STMicroelectronics