74.10.2.1 Power Consumption in BSR Mode

Figure 74-54. Measurement on VBAT and VDDIODDR

Power consumption on AMP1 is provided in section Backup Mode. Only AMP2 measures are relevant in this section. The following table shows the result of average current measurements performed on a few typical devices.

Table 74-78. Typical Current Consumption in BSR Mode on VDDIODDR
VDDIODDR (V) TJ=-40°C TJ= 25°C TJ= 50°C TJ= 70°C TJ=85°C TJ=105°C TJ=125°C Unit
1.35V < 1 2 5 15 30 75 140 µA

The following operations, based on procedures described in SDRAM Self-Refresh Mode, must be performed in this order. Code example is provided in software deliverables.

Entering Backup with SDRAM in Self-Refresh Mode

  1. Enter Self-refresh mode with I/O power-down as described in the "Entering Self-Refresh Mode with I/O Power-down" procedure (see SDRAM Self-Refresh Mode).
  2. Enter Backup mode:
    • Write a special code (0x12345678, for example) in a backup register to identify the BSR state.
    • Disable SYSC write protection.
    • Clear the SHDWC Control register.
    • Configure the wake-up source.
    • Send Shutdown and LPM Enable commands to the SHDWC Control register.
    Note: After wake-up, the device performs a system reset.
  3. Re-initialize SDRAM and exit Self-refresh mode: refer to "High-Level SDRAM Initialization Procedure" in the section Universal DDR Memory Controller (UDDRC).