SPRUI30H November 2015 – May 2024 DRA745 , DRA746 , DRA750 , DRA756
The RTC is connected to four external system wake-up signals. The RTC also can operate on external 32-kHz clock and has dedicated power-on reset pin. An external control of the RTC isolation cells is available to isolate RTC from other power domains when the PD_RTC is the only powered domain.
The RTC module can be configured to produce a power-up/down control signal for the power-management chip (PMIC, if present).
Table 23-1 summarizes the external signals received and produced by the RTC module.
Device-Level Pin | Module-Level Signal | I/O | Description |
---|---|---|---|
rtc_osc_xi_clkin32 | RTC_32K_CLK | I | RTC clock input |
rtc_osc_xo | —(1) | O | 32k oscillator crystal driver output. Unused if clock is provided from external source (crystal not connected) |
wakeup0 | EXT_WAKEUP0 | I | External wake-up signal |
wakeup1 | EXT_WAKEUP1 | I | External wake-up signal |
wakeup2 | EXT_WAKEUP2 | I | External wake-up signal |
wakeup3 | EXT_WAKEUP3 | I | External wake-up signal |
on_off | PMIC_PWR_ENABLE | O | Companion PMIC control output (on/off) (optional) |
rtc_porz | RTC_POR_ARST | I | External power-on-reset input (optional) |
rtc_iso | —(2) | I | External control of isolation cells. This signal must be kept low (0) during RTC mode and high (1) after the device power supplies ramped-up. This can typically be achieved by connecting rtc_iso to the porz (not rtc_porz) with appropriate voltage level translation if necessary. |
Figure 23-2 shows the described signals.