ICM-20690
12.74 REGISTERS 114 AND 115 – FIFO COUNT REGISTERS
Register Name: FIFO_COUNTH
Register Type: READ
Register Address: 114 (Decimal); 72 (Hex)
BIT
NAME
FUNCTION
High Bits, count indicates the number of written bytes in the FIFO.
Reading this byte latches the data for both FIFO_COUNTH, and FIFO_COUNTL.
[7:0]
FIFO_COUNT[15:8]
Register Name: FIFO_COUNTL
Register Type: READ
Register Address: 115 (Decimal); 73 (Hex)
BIT
NAME
FUNCTION
Low Bits, count indicates the number of written bytes in the FIFO.
Note: Must read FIFO_COUNTL to latch new data for both FIFO_COUNTH and
FIFO_COUNTL.
[7:0]
FIFO_COUNT[7:0]
12.75 REGISTER 116 – FIFO READ WRITE
Register Name: FIFO_R_W
Register Type: READ/WRITE
Register Address: 116 (Decimal); 74 (Hex)
BIT
NAME
FUNCTION
[7:0]
FIFO_DATA
Read/Write command provides Read or Write operation for the FIFO.
Description:
This register is used to read and write data from the FIFO buffer.
Data is written to the FIFO in order of register number (from lowest to highest). If all the FIFO enable flags (see below) are
enabled, the contents of registers 59 through 72 will be written in order at the Sample Rate.
The contents of the sensor data registers (registers 59 to 72) are written into the FIFO buffer when their corresponding FIFO
enable flags are set to 1 in FIFO_EN (Register 35).
If the FIFO buffer has overflowed, the status bit FIFO_OFLOW_INT is automatically set to 1. This bit is located in INT_STATUS
(Register 58). When the FIFO buffer has overflowed, the oldest data will be lost and new data will be written to the FIFO
unless register 26 CONFIG, bit[6] FIFO_MODE = 1.
If the FIFO buffer is empty, reading register FIFO_DATA will return a unique value of 0xFF until new data is available.
Normal data is precluded from ever indicating 0xFF, so 0xFF gives a trustworthy indication of FIFO empty.
Page 68 of 76
Document Number: DS-000178
Revision: 1.0
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