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Datasheet of MCIMX53SMD - TABLET SABRE PLATFORM MCIMX53
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30
MCIMX53SMD Board Hardware User’s Guide, Rev. 0
Freescale Semiconductor
which power must be supplied to the i.MX53 processor. Once the core operations of the processor are fully
powered, other power rails can be turned ON.
The first voltage regulator to power ON is always VLDO1. This regulator supplies a maximum of 40 mA current
at 1.3V and powers ON only the Secure RTC module of the i.MX53 processor. This turns ON the RTC Clock
(32.768 kHz) and Watch Dog features. If a system reset is triggered, or the MCIMX53SMD board is placed into
the standby mode, VLDO1 will remain powered ON. VLDO1 will turn OFF only if all power is removed from the
MCIMX53SMD board, or if a software command is sent to the PMIC to turn OFF VLDO1. In case, the developer
attaches an optional coin cell (BT1), the coin cell will provide the necessary power to keep VLDO1 operating.
The power sequence requirements for the i.MX53 processor (as specified in the i.MX53 data sheet) are as
follows:
1.
NVCC_SRTC_POW (VLDO1)
2.
VCC, VDDA, VDDGP (in any order)
3.
NVCC_CKIH, VDD_REG (in any order)
4.
All other supplies (in any order)
NOTE
In case the internal regulator is used for VDDA generation, the VDD_REG should be powered
up together with VCC and VDDGP, before other supplies. If the internal regulator is not used
to generate VDDA (as on the MCIMX53SMD board), the VDD_REG is independent and has no
power-up restrictions.
The power up timing sequence shown in
Table 5-1
is the sequence programmed into the Dialog PMIC. It is one
way of providing power sequences to the i.MX53 processor. Designers are free to change the power timing
sequence on their own board designs as long as the timing requirements are met. Freescale has not formally
tested other power up timing sequences.
Regulator
Time Slot
VBUCKPRO
19 mSEC
VBUCKPERI
VLDO6
VLDO8
VLDO10
23 mSEC
VBUCKCORE
27 mSEC
VBUCKMEM
VBUCKPERI/SW
VLDO2
VLDO5
31 mSEC
VLDO4
VLDO7
35 mSEC
VLDO3
VLDO9
64 mSEC
Table 5-1.
Regulator Timing Sequence
The Dialog PMIC enters a SHUTDOWN/STANDBY condition in three ways:
By a command from the i.MX53 processor through
I2C communications
By i.MX53 processor action to hold the nONKEY/KEEPACT pin low for at least five seconds
By hardware if the user holds down the POWER button for more than five seconds
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