3.3. RTC & Power-Button¶
| Pin | Signal | Description | type | I/O | |||||
|---|---|---|---|---|---|---|---|---|---|
| 13 | VBACKUP | DS1339 RTC backup power supply. Supply voltage must be held between 1.3V and 3.7V for proper RTC operation. This pin can be connected to a primary cell such as a lithium button cell. Additionally, this pin can be connected to a rechargeable cell or a super cap when used with the trickle charge feature. Refer to DS1339 datasheet for details. | power | I | |||||
| Module | Remark | ||||||||
| TX25 | Connected to BAT_VDD DRYICE backup power supply input, max. 1.55V The i.MX25 internal RTC is not supported | ||||||||
| TX6 without DS1339 | i.MX6 RTC backup power supply. Supply voltage must be held between 2.9V and 3.3V for proper RTC operation. | ||||||||
| 14 | PMIC_PWR_ON | PMIC dependent Function. Leave unconnected if not used. | I | ||||||
| Module | Remark | ||||||||
| TX25 | No PMIC onboard - Not connected | ||||||||
| TX28 | PSWITCH - Used for chip power on or recovery. PSWITCH is at MID level by default. Refer to i.MX28 reference manual for details. | ||||||||
| TX27, TX51 | This is an active high push button input which can be used to signal PWR_ON and PWR_OFF events to the CPU by controlling the PMIC EXT_WAKEUP. Refer to LP3972 datasheet, page 49 for details. | ||||||||
| TX48, TX53 | Connected to LTC3589 WAKE. To power down, drive this pin LOW. Refer to LTC3589 datasheet, page 29 for details. | ||||||||
| TX6 | Connected to PMIC ON. Refer to PMIC datasheet for details. | ||||||||
