SLVUBY7A October   2020  – October 2022 DRA821U , DRA821U-Q1 , LP8764-Q1 , TPS6594-Q1

 

  1.   User's Guide for Powering DRA821 with TPS6594-Q1 and LP8764-Q1
  2.   Trademarks
  3. 1Introduction
  4. 2Device Versions
  5. 3Processor Connections
  6. 4Supporting Functional Safety Systems
    1. 4.1 Achieving ASIL-B System Requirements
    2. 4.2 Achieving up to ASIL-D System Requirements
  7. 5Static NVM Settings
    1. 5.1  Application-Based Configuration Settings
    2. 5.2  Device Identification Settings
    3. 5.3  BUCK Settings
    4. 5.4  LDO Settings
    5. 5.5  VCCA Settings
    6. 5.6  GPIO Settings
    7. 5.7  Finite State Machine (FSM) Settings
    8. 5.8  Interrupt Settings
    9. 5.9  POWERGOOD Settings
    10. 5.10 Miscellaneous Settings
    11. 5.11 Interface Settings
    12. 5.12 Multi-Device Settings
    13. 5.13 Watchdog Settings
  8. 6Pre-Configurable Finite State Machine (PFSM) Settings
    1. 6.1 Configured States
    2. 6.2 PFSM Triggers
    3. 6.3 Power Sequences
      1. 6.3.1 TO_SAFE_SEVERE
      2. 6.3.2 TO_SAFE_ORDERLY and TO_STANDBY
      3. 6.3.3 ACTIVE_TO_WARM
      4. 6.3.4 ESM_SOC_ERROR
      5. 6.3.5 PWR_SOC_ERROR
      6. 6.3.6 MCU_TO_WARM
      7. 6.3.7 TO_MCU
      8. 6.3.8 TO_ACTIVE
      9. 6.3.9 TO_RETENTION
  9. 7Application Examples
    1. 7.1 Moving Between States: ACTIVE, MCU, and RETENTION
      1. 7.1.1 ACTIVE
      2. 7.1.2 MCU ONLY
      3. 7.1.3 RETENTION
    2. 7.2 Entering and Exiting Standby
    3. 7.3 Entering and Existing LP_STANDBY
    4. 7.4 GPIO8 and Watchdog
  10. 8Additional Resources
  11. 9Revision History

ACTIVE_TO_WARM

The ACTIVE_TO_WARM sequence can be triggered by either a watchdog or ESM_MCU error. In the event of a trigger, the nRSTOUT and nRSTOUT_SOC signals are driven low and the recovery count (register RECOV_CNT_REG_1) increments. Then, all BUCKs and LDOs are reset to their default voltages. The PMICs remain in the ACTIVE state.

Note: GPIOs do not reset during the sequence as shown in Figure 6-4.

At the beginning of the sequence the following instructions are executed:

//TPS6594141B
// Set FORCE_EN_DRV_LOW
REG_WRITE_MASK_IMM ADDR=0x82 DATA=0x08 MASK=0xF7
// Clear nRSTOUT and nRSTOUT_SOC
REG_WRITE_MASK_IMM ADDR=0x81 DATA=0x00 MASK=0xFC
// Increment the recovery counter
REG_WRITE_MASK_IMM ADDR=0xa5 DATA=0x01 MASK=0xFE

Note: The watchdog or ESM error is an indication of a significant error which has taken place outside of the PMIC. The PMIC does not actually transition through the safe recovery as with an MCU_POWER_ERR, however, in order to maintain consistency all of the regulators are returned to the values stored in NVM and the recovery counter is incremented. If the recovery counter exceeds the recovery count threshold the PMICs stay in the safe recovery state.

Note: After the ACTIVE_TO_WARM sequence the MCU is responsible for managing the EN_DRV and recovery counter. At the end of the sequence the 'FORCE_EN_DRV_LOW' bit is cleared so that the MCU can set the ENABLE_DRV bit.

Figure 6-4 ACTIVE_TO_WARM Sequence

Note: The regulator transitions do not represent enabling of the regulators but the time at which the voltages are restored to their default values. Since this sequence originates from the ACTIVE state all of the regulators are on.