TSL2521 ALS/Flicker
Flicker Result Data Format
Application Note
• PUBLIC
AN001042
• v1-01 • 2022-Jan-27
23
│ 19
4
Flicker Result Data Format
4.1
Internal Flicker Data Format
Flicker data is at maximum 15 bits large as shown in Figure 14
– again 4-bit Residuals on LSB side
and maximum 11-bit for full counts since the field sample_time is 11-bit wide. Internally these
maximum 15 bits are stored in a 16-bit data register.
Figure 14:
16-Bit Flicker Data Format
Note that the lower 4 bits are always reserved for Residual bits, no matter, if they are really measured
or if the measurement is reduced to a lower number of Residual bits.
4.2
Flicker Data Reduction Options
There are several possibilities to reduce the number of transferred flicker data bits in order to reduce
I
2
C traffic. For high flicker samples rates the dynamic range is lower, so the absolute number of bits of
a transferred sample can be set lower. The bit width for flicker data in the FIFO is set by field [3:0]
mod_fd_fifo_datax_width of register MOD_FIFO_DATA_CFGx. The default value is 15, which means
the full 16-bit wide word shown in Figure 14. Figure 15 shows an example for 11-bit flicker data width,
which would be suitable for the requirements of the example specification in Figure 9.
Figure 15:
Flicker Data Format with 11-Bit Width as Example
14 13 12 11 10 9
8
7
6
5
4
3
2
1
Full counts
Residuals
Internal 16 bit flicker data format:
0
15
14 13 12 11 10 9
8
7
6
5
4
3
2
1
Full counts
Residuals
Internal 16 bit flicker data format:
0
mod_fd_fifo_datax_width = 10
9
8
7
6
5
4
3
2
1
Full counts
Residuals
0
Flicker data on FIFO:
10
15
