Remember: The user must force VDDMMC at 3.3 V when using any of these functions:
• OCSPI1: Refer to Section 7.7 .
• LED1: Refer to Section 7.10 .
• Camera: Refer to Section 7.11 .
• MEMS LED and DFSDM: Refer to Section 7.2 .
• SRAM (FMC_NE3): Refer to Section 8.1 .
• OCSPI2: Refer to Section 8.6 .
• Motor control: Refer to Section 8.8 .
Table 13. VDDMMC default hardware configuration for '3.3V only' functions
Signal name
Setting
VDDMMC = '3.3 V only'
(1)
OCSPI1_NCS (PG6) JP23 [1-2]
3V3_SW_ENABLE (MFX IO0) SB34
ON
(2)
1V8_SW_ENABLE (MFX IO8) SB29
ON
(2)
1. The default setting is in bold.
2. PB8 signal is supplied by VDDMMC. Make sure to supply 3.3V on VDDMMC (Refer to Section 6.3.5 ).
Three possibilities to force VDDMMC to 3.3V:
1. Default configuration: Software control (Without hardware modification). In this case, the user must follow
the hardware configuration described in Table 13:
– Set 3V3_SW at 3.3 V by software: 3V3_SW_ENABLE (MFX IO0) = 1 (3V3_SW = ON).
2. Hardware modification to force 3V3_SW to be 'always ON'. If the user prefers 3V3_SW power supply to be
always ON:
– Remove SB34 or set MFX IO0 in high impedance mode (R130 pull-up resistor forces the enable of
U14 LDO).
Remember:
In this configuration, the user cannot perform a “power OFF” of 3.3 V supply for SDIO2.
3. Hardware modification to force VDDMMC to 3.3 V (3V3_AO). If the user wants VDDMMC MCU pin to
remain always at 3.3 V without controlling MFX IO0:
– Remove SB14 and fit SB15 in order to connect this pin to the 3V3_AO power supply.
Remember: In this configuration, the user cannot use SDIO2 at 1.8 V.
SDIO2 configuration (VDDMMC = 1V8_SW or 3V3_SW)
3V3_SW, 1V8_SW and VDDMMC are set up in order to allow controlling various use-cases with SDIO2 interface,
including power OFF sequence, automatic detection of a UHS1 SD card, and switch from 3.3 V to 1.8 V (Refer to
chapter 3.3).
Table 14. SDIO2 pins supplied by VDDMMC (1.8V or 3.3V)
Pin name
Pin function
PD6 SDIO2_CK
PD7 SDIO2_CMD
PG9 SDIO2_D0
PG10 SDIO2_D1
PG11 SDIO2_D2
PG12 SDIO2_D3
UM2662
Power supply
UM2662 - Rev 1
page 24/95
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