VDD2
VDDS
SDMMC1_VDDS
/ SIM_VDDS
PWRDNZ
X
scm-021
Public Version
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SCM Programming Model
Table 13-68. PBIAS Error Signal Truth Table (continued)
VMODE
PWRDNZ
SUPPLY_HIGH
PBIAS ERROR
X
1
X
1
1
0
X
0
1
1
0
1
1
1
1
0
NOTE:
PBIAS ERROR = 1: VMODE level not same as SUPPLY_HIGH
PBIAS ERROR = 0: VMODE level same or VMODE not considered
The PBIAS errors, PBIAS0_ERROR and PBIAS_ERROR1, are merged and connected to the MPU
subsystem interrupt controller.
The CONTROL.
[i] PBIASLITEVMODEERROR (where i = 3 or 11) bits also
indicate if this kind of error occurs.
13.5.2.2 Critical Timing Requirements
It is crucial that the PBIAS and I/O cell related PWRDNZ bits are deasserted (made 1 from 0) only after
SDMMC1_VDDS/SIM_VDDS is stable. The device supports only the power-up sequence in which VDD2
ramps up before VDDS. However, SDMMC1_VDDS/SIM_VDDS must come up after both VDD2 and
VDDS.
show the expected behavior of PWRNDZ bit with regard to supply ramp up. This figure also
shows the only possible combination when VDDS ramps up before VDD2.
Figure 13-25. VDDS Ramps Up Before VDD2
NOTE:
These timing requirements are applicable only when SDMMC1_VDDS/SIM_VDDS is 3.0 V.
If SDMMC1_VDDS/SIM_VDDS is 1.8 V, VDDS and SDMMC1_VDDS/SIM_VDDS can be
ramped up simultaneously.
13.5.2.3 Speed Control and Voltage Supply State
There are other control bits, PRG_SDMMC1_SPEEDCTRL in the CONTROL.
and
SUPPLYHIGH in the CONTROL.
registers:
•
PRG_SDMMC1_SPEEDCTRL bit can be used to reduce dynamic current if fast rise/fall times are not
needed.
•
SUPPLYHIGH bit signal is used to inform the cell on the value of SDMMC1_VDDS/SIM_VDDS signal
(0b0 = 1.8 V and 0b1 = 3.0 V).
13.5.3 Off Mode Preliminary Settings
The following actions must be performed once, and remain valid for all device OFF <-> ON transitions:
2539
SWPU177N – December 2009 – Revised November 2010
System Control Module
Copyright © 2009–2010, Texas Instruments Incorporated