AN4504 datasheet(29/41 Pages) STMICROELECTRONICS

Part #	AN4504

Description	This document is intended to provide usage information

PDF	41 Pages

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Manufacturer	STMICROELECTRONICS [STMicroelectronics]

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AN4504

First-in first-out (FIFO) buffer

Figure 13. FIFO_EN connections block diagram

6.2.2

FIFO control register (0x2E)

This register is dedicated to FIFO mode selection and watermark configuration.

The FM[2:0] bits are dedicated to defining FIFO buffer behavior:

FM[2:0] = (0,0,0): Bypass mode

FM[2:0] = (0,0,1): FIFO mode

FM[2:0] = (0,1,0): Stream mode

FM[2:0] = (0,1,1): Stream-to-FIFO mode

FM[2:0] = (1,0,0): Bypass-to-Stream

The trigger used to activate the Stream-to-FIFO and Bypass-to-Stream modes is related to

the IA bit value of the selected INT1_SRC register and does not depend on the interrupt pin

value and polarity. The trigger is generated also if the selected interrupt is not driven to an

interrupt pin.

The WTM[4:0] bits are intended to define the watermark level; when FIFO content exceeds

this value, the WTM bit is set to “1” in the FIFO source register.

Table 29. FIFO_CTRL_REG

FM2

FM1

FM0

WTM4

WTM3

WTM2

WTM1

WTM0

AN4504 Datasheet(PDF) 29 Page - STMicroelectronics