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TMS320C6670 Peripheral Information and Electrical Specifications
Copyright 2012 Texas Instruments Incorporated
SPRS689D—March 2012
Multicore Fixed and Floating-Point System-on-Chip
TMS320C6670
7.2.1 Power-Up Sequencing
This section defines the requirements for a power up sequencing from a power-on reset condition. There are two
acceptable power sequences for the device. The first sequence stipulates the core voltages starting before the IO
voltages as shown below.
1.
CVDD
2.
CVDD1, VDDT1-3
3.
DVDD18, AVDD1, AVDD2
4.
DVDD15, VDDR1-6
The second sequence provides compatibility with other TI processors with the IO voltage starting before the core
voltages as shown below.
1.
DVDD18, AVDD1, AVDD2
2.
CVDD
3.
CVDD1, VDDT1-3
4.
DVDD15, VDDR1-6
The clock input buffers for SYSCLK, ALTCORECLK, DDRCLK, PASSCLK, SRIOSGMIICLK, PCIECLK, and
MCMCLK use CVDD as a supply voltage. These clock inputs are not failsafe and must be held in a high-impedance
state until CVDD is at a valid voltage level. Driving these clock inputs high before CVDD is valid could cause damage
to the device. Once CVDD is valid, it is acceptable that the P and N legs of these clocks may be held in a static state
(either high and low or low and high) until a valid clock frequency is needed at that input. To avoid internal
oscillation, the clock inputs should be removed from the high impedance state shortly after CVDD is present.
If a clock input is not used, it must be held in a static state. To accomplish this, the N leg should be pulled to ground
through a 1-k
Ω
resistor. The P leg should be tied to CVDD to ensure it will not have any voltage present until CVDD
is active. Connections to the IO cells powered by DVDD18 and DVDD15 are not failsafe and should not be driven
high before these voltages are active. Driving these IO cells high before DVDD18 or DVDD15 are valid could cause
damage to the device.
The device initialization is divided into two phases. The first phase consists of the time period from the activation of
the first power supply until the point at which all supplies are active and at a valid voltage level. Either of the
sequencing scenarios described above can be implemented during this phase. The figures below show both the
core-before-IO voltage sequence and the IO-before-core voltage sequence. POR must be held low for the entire
power stabilization phase.
This is followed by the device initialization phase. The rising edge of POR followed by the rising edge of RESETFULL
will trigger the end of the initialization phase but both must be inactive for the initialization to complete. POR must
always go inactive before RESETFULL goes inactive as described below. SYSCLK1 in the following section refers to
the clock that is used by the CorePac, see
for more details.
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