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Document number: BST-BMP390-DS002-07 Revision_1.7_032021

Table 18: Control frame: configuration error

Bit

Header

Opcode

If FIFO is enabled and a change in registers “FIFO_CONF_2” or “OSR” or “ODR” or “CONFIG” or press_en or temp_en

occurs, a control frame is inserted just before the first sensor frame with new configuration is stored to the FIFO. If multiple

configuration change becomes active at the same time, only one control frame is inserted. Configuration changes are tracked

when the device is in normal mode.

3.6.6. Corner cases

3.6.6.1. Under-read

In case the FIFO is under-read (not all frames were taken from the FIFO, but the last frame read was read entirely), the next

readout will continue at the frame that was just about to be sent.

3.6.6.2. Partial frame read

In case the FIFO is under-read and a partial data frame read occurred (not all frames were taken from the FIFO, and the last

frame read was not read entirely), the entire last data frame is repeated upon the next read access.

When fifo_stop_on_full=’0’, the oldest frames are overwritten when new frames are available and the FIFO is full. When this

happens, the partially read data frame is not repeated but the oldest frame available in the RAM is sent instead.

Sensortime frame is not repeated when read only partially, its payload always contains current sensortime counter value.

If the read of the frame is interrupted after two or more bits of the frame’s last byte were already read, then frame is discarded

even though not all bits were read and the frame was read only partially.

3.6.6.3. Over-read

If the burst read continues after all frames have been read out, a sensortime frame is sent after the FIFO becomes empty

during a burst read operation if fifo_time_en=’1’. After that or when FIFO was completely read, the empty frame is returned

as long as the burst read is

active.

3.6.7. FIFO flush conditions

The FIFO can be flushed by issuing either fifo_flush or a softreset in the command register “CMD” (see 4.3.23):

Table 19: fifo_fluch and softreset commands

Value

fifo_flush

0xB0

softreset

0xB6

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