
Start
Set the PWRDNZ bit to 0x0
Type of transition?
1.8 V to 3.0 V
3.0 V to 1.8 V
Set the VMODE bit to 0x0
Set the VMODE bit to 0x1
Set the PWRDNZ bit to 0x1
Change the SDMMC1_VDDS
/SIM_VDDS voltage
Is SDMMC1_VDDS
/SIM_VDDS
stable?
No
Yes
The voltage stability
is handled by the
power IC device, not by
the multimedia device.
End
scm-019
Public Version
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SCM Programming Model
Table 13-67. Voltage Configuration
(1)
(continued)
PBIASLITEVMODE Configuration
SDMMC1_VDDS/SIM_VDDS Voltage
Reset Value
3.0 V
1.8 V
Degraded functionality
(2)
3.0 V
3.0 V
Normal 3.0-V operation
describes the programming flow to go from 3.0 V to 1.8 V, and vice versa.
Figure 13-24. Flow Chart
The PBIAS output is the same as SDMMC1_VDDS/SIM_VDDS when the corresponding PBIAS cell
related PWRDNZ bitis LOW. Once the SDMMC1_VDDS/SIM_VDDS supply settles, software releases the
PWRNDZ (pulls it HIGH). This then starts up the PBIAS cell work to generate the PBIAS voltage. During
the complete process the corresponding I/Os cannot be used to transmit data.
NOTE:
In the case of a damaging configuration, hardware system protection prevents deterioration
of the associated extended-drain I/Os.
2537
SWPU177N – December 2009 – Revised November 2010
System Control Module
Copyright © 2009–2010, Texas Instruments Incorporated