This register controls the power state of the 4 power domains. The current power state is indicated in POWMAN_STATE_CURRENT which is read-only. To change the state, write to POWMAN_STATE_REQ. The coding of POWMAN_STATE_CURRENT & POWMAN_STATE_REQ corresponds to the power states defined in the datasheet: bit 3 = SWCORE bit 2 = XIP cache bit 1 = SRAM0 bit 0 = SRAM1 0 = powered up 1 = powered down When POWMAN_STATE_REQ is written, the POWMAN_STATE_WAITING flag is set while the Power Manager determines what is required. If an invalid transition is requested the Power Manager will still register the request in POWMAN_STATE_REQ but will also set the POWMAN_BAD_REQ flag. It will then implement the power-up requests and ignore the power down requests. To do nothing would risk entering an unrecoverable lock-up state. Invalid requests are: any combination of power up and power down requests any request that results in swcore boing powered and xip unpowered If the request is to power down the switched-core domain then POWMAN_STATE_WAITING stays active until the processors halt. During this time the POWMAN_STATE_REQ field can be re-written to change or cancel the request. When the power state transition begins the POWMAN_STATE_WAITING_flag is cleared, the POWMAN_STATE_CHANGING flag is set and POWMAN register writes are ignored until the transition completes.
CURRENT | |
REQ | |
REQ_IGNORED | |
PWRUP_WHILE_WAITING | Request ignored because of a pending pwrup request. See current_pwrup_req. Note this blocks powering up AND powering down. |
BAD_SW_REQ | Bad software initiated state request. No action taken. |
BAD_HW_REQ | Bad hardware initiated state request. Went back to state 0 (i.e. everything powered up) |
WAITING | |
CHANGING |