The device has four power modes plus an Complete Off state. The functions supported under each power modes are summarized in Table 7-1 and the power state diagram is shown in Figure 7-2.
- COMPLETE OFF: The voltage at the BAT pin is less than VBAT min, and all circuits are powered off.
- SHUTDOWN: The lowest power mode. Without VIO, device can only transition to VALIDATE. (If Sniffer used)
- SLEEP: A low power mode. Transition to ACTIVE is much faster compared
to SHUTDOWN.
- ACTIVE: Full power mode. Device can communicate between MCU and daisy chain.
- VALIDATE: This state is to validate if there is real fault tone from
stack devices. If fault tone is validated, drive INH pin towards VBAT (INH pin
is latched until cleared by user). Device goes back to SHUTDOWN if
tVALID_TIMEOUT or sleep timer expires. (tVALID_TIMEOUT
timer is reset if fault tone is detected, detecting Heartbeat tone doesn’t reset
timer.) This state is bypassed if Section 7.3.5 is disabled (by default). Once entered this state, a status bit
[VALIDATE_DET] is set in next ACTIVE such that host knows what happened. Without
VIO, device can only transition to SHUTDOWN. NFAULT pin is low in this
mode.
Table 7-1 Functions SummaryFUNCTIONAL BLOCK(1) | SHUTDOWN | VALIDATE(3) | SLEEP | ACTIVE |
---|
Data Communication RX/TX | | | | If VIO_UV_R = 1 |
Time out | | Sleep Timeout | Sleep Timeout | Comm Timeout |
Tone RX (HB/Fault) | | √ | Depends on [DIR_SEL] and
[TONE_RX_EN] |
Tone TX (WAKE/ SLP2ACT/ SHUTDOWN/ HWRST) (5) | | | | √ |
Tone TX (HB) | | | Depends on [DIR_SEL] and [HB_TX_EN] | |
COM embedded fault | | | | [FCOMM_EN] =1 |
Sniff detector on COM* | If host enables this feature (2) | | | |
Wake/Shutdown Ping | If VIO_UV_R = 1 | If VIO_UV_R = 1 | If VIO_UV_R = 1 | If VIO_UV_R = 1 |
SLP2ACT Ping | | | √ | |
NFAULT Driver | | √ | √ | √ |
LFO | | √ | √ | √ |
HFO | | | | √ |
INH Driver | Holds State | √ | INH_DIS[1:0] != 2’b11 | INH_DIS[1:0] != 2’b11(4) |
CVDD/DVDD | | √ | √ | √ |
Thermal Shutdown | | √ | √ | √ |
(1) Once device in SLEEP/ACTIVE, losing VIO doesn’t directly cause change of state,
it causes loss of data communication to MCU.
(2) If host writes [SNIFDET_EN] =1 & [SNIFDET_DIS] = 0 in ACTIVE mode, even
device shuts down, enable signal is still valid. Sniff detector is enabled or
disabled by a latch powered by always on power supply.
(3) This mode is bypassed if sniff detector is not enabled, see register
DEV_CONF1.
(4) INH can only be triggered by [INH_SET_GO] bit in ACTIVE.
(5) Device does not recognize WAKE/ SLP2ACT/ SHUTDOWN/ HWRST tone sent by stack
devices.