ZHCSJ72A December 2018 – December 2021 OPT3004
PRODMIX
The latched window-style comparison mode is typically selected when using the OPT3004 to interrupt an external processor. In this mode, a fault is recognized when the input signal is above the high-limit register or below the low-limit register. When the consecutive fault events trigger the interrupt reporting mechanisms, these mechanisms are latched, thus reporting whether the fault is the result of a high or low comparison. These mechanisms remain latched until the configuration register is read, which clears the INT pin and flag high and flag low fields. The SMBus alert response protocol, described in detail in the SMBus Alert Response section, clears the pin but does not clear the flag high and flag low fields. The behavior of this mode, along with the conversion ready flag, is summarized in Table 8-2. Note that Table 8-2 does not apply when the two threshold low register MSBs (see the Transparent Hysteresis-Style Comparison Mode section for clarification on the MSBs) are set to 11b.
OPERATION | FLAG HIGH FIELD | FLAG LOW FIELD | INT PIN(1) | CONVERSION READY FIELD |
---|---|---|---|---|
The result register is above the high-limit register for fault count times. See the Result Register and the High-Limit Register for further details. | 1 | X | Active | 1 |
The result register is below the low-limit register for fault count times. See the Result Register and the Low-Limit Register for further details. | X | 1 | Active | 1 |
The conversion is complete with fault count criterion not met | X | X | X | 1 |
Configuration register read(3) | 0 | 0 | Inactive | 0 |
Configuration register write, M[1:0] = 00b (shutdown) | X | X | X | X |
Configuration register write, M[1:0] > 00b (not shutdown) | X | X | X | 0 |
SMBus alert response protocol | X | X | Inactive | X |