JAJSNU4A May 2023 – June 2024 AFE78201 , AFE88201
PRODUCTION DATA
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The AFEx8201 provides an alarm action configuration register: ALARM_ACT, Table 7-15. Writing to this register selects the device action that automatically occurs for a specific alarm condition. The ALARM_ACT register determines how the main DAC responds to an alarm event from either an ADC conversion on the self-diagnostics channels (AIN0, AIN1, and TEMP), or from a CRC, WDT, VREF, TEMP_HI, or TEMP_LO fault. Only these faults cause a response by the DAC. Any other alarm status events trigger the ALARM pin. There are four options for alarm action. In case different settings are selected for different alarm conditions, the following low-to-high priority is considered when taking action:
If option 1 is selected when the alarm event occurs, then the DAC is forced to the clear code. This operation is done by controlling the input code to the DAC.
If option 2 is selected when the alarm event occurs, then VOUT is forced to the alarm voltage. The alarm voltage is controlled by either pin or register bit. If SPECIAL_CFG.AIN1_ENB = 0, then the AIN1 pin controls alarm polarity. Also, register bit SPECIAL_CFG.ALMV_POL can be used. If either of these signals = 1, then the alarm voltage is high; otherwise, the alarm voltage is low. The SPECIAL_CFG register is only reset with POR, so the user setting remains intact through hardware or software resets.
If option 3 is selected when the alarm event occurs, then the VOUT buffer is put into Hi-Z. If multiple events occur, then the highest setting takes precedence. Option 3 has the highest priority.
To disable action response to an alarm, set the corresponding bits in ALARM_ACT to 0h. Alarm action response is cleared either when the triggered condition bit resets (behavior depends on whether the fault bit in ALARM_STATUS is sticky or not), or by changing the action configuration to 0h.
An alarm action, as configured, executes when an alarm occurs depending on ALARM_STATUS and ALARM_ACT registers. Action response is independent of ALARM_STATUS_MASK settings.