ZHCSQM3 December 2022 OPT3005
PRODUCTION DATA
This register sets the lower comparison limit for the interrupt reporting mechanisms: the INT pin, the flag high field (FH), and flag low field (FL), as described in the Interrupt Reporting Mechanism Modes section.
| 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 |
| LE3 | LE2 | LE1 | LE0 | TL11 | TL10 | TL9 | TL8 |
| R/W | R/W | R/W | R/W | R/W | R/W | R/W | R/W |
| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| TL7 | TL6 | TL5 | TL4 | TL3 | TL2 | TL1 | TL0 |
| R/W | R/W | R/W | R/W | R/W | R/W | R/W | R/W |
| LEGEND: R/W = Read/Write |
| Bit | Field | Type | Reset | Description |
|---|---|---|---|---|
| 15:12 | LE[3:0] | R/W | 0h | Exponent. These bits are the exponent bits. Table 8-12 provides further details. |
| 11:0 | TL[11:0] | R/W | 000h | Result. These bits are the result in straight binary coding (zero to full-scale). |
The format of this register is nearly identical to the format of the result register described in the Result Register. The low-limit register exponent (LE[3:0]) is similar to the result register exponent (E[3:0]). The low-limit register result (TL[11:0]) is similar to result register result (R[11:0]).
The equation to translate this register into the lux threshold is given in Equation 4, which is similar to the equation for the result register, Equation 3.
Table 8-12 gives the full-scale range and LSB size as it applies to the low-limit register. The detailed discussion and examples given in for the Result Register apply to the low-limit register as well.
| LE3 | LE2 | LE1 | LE0 | FULL-SCALE RANGE (lux) | LSB SIZE (lux per LSB) |
|---|---|---|---|---|---|
| 0 | 0 | 0 | 0 | 81.90 | 0.02 |
| 0 | 0 | 0 | 1 | 163.80 | 0.04 |
| 0 | 0 | 1 | 0 | 327.60 | 0.08 |
| 0 | 0 | 1 | 1 | 655.20 | 0.16 |
| 0 | 1 | 0 | 0 | 1310.40 | 0.32 |
| 0 | 1 | 0 | 1 | 2620.80 | 0.64 |
| 0 | 1 | 1 | 0 | 5241.60 | 1.28 |
| 0 | 1 | 1 | 1 | 10483.20 | 2.56 |
| 1 | 0 | 0 | 0 | 20966.40 | 5.12 |
| 1 | 0 | 0 | 1 | 41932.80 | 10.24 |
| 1 | 0 | 1 | 0 | 83865.60 | 20.48 |
| 1 | 0 | 1 | 1 | 167731.2 | 40.96 |
The result and limit registers are all converted into lux values internally for comparison. These registers can have different exponent fields. However, when using a manually-set full-scale range (configuration register, RN < 0Ch, with mask enable (ME) active), programming the manually-set full-scale range into the LE[3:0] and HE[3:0] fields can simplify the choice of programming the register. This simplification results in the user only having to think about the fractional result and not the exponent part of the result.