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TMS320C6670
Multicore Fixed and Floating-Point System-on-Chip
SPRS689D—March 2012
Table 7-2
Core Before IO Power Sequencing
Time
System State
1
Begin Power Stabilization Phase
• CVDD (core AVS) ramps up.
• POR must be held low through the power stabilization phase. Because POR is low, all the core logic that has async reset (created from
POR) is put into the reset state.
2a
• CVDD1 (core constant) ramps at the same time or shortly following CVDD. Although ramping CVDD1 and CVDD simultaneously is
permitted, the voltage for CVDD1 must never exceed CVDD until after CVDD has reached a valid voltage.
• The purpose of ramping up the core supplies close to each other is to reduce crowbar current. CVDD1 should trail CVDD as this will
ensure that the WLs in the memories are turned off and there is no current through the memory bit cells. If, however, CVDD1 (core
constant) ramps up before CVDD (core AVS), then the worst-case current could be on the order of twice the specified draw of CVDD1.
2b
• Once CVDD is valid, the clock drivers should be enabled. Although the clock inputs are not necessary at this time, they should either be
driven with a valid clock or be held in a static state with one leg high and one leg low.
2c
• The DDRCLK and SYSCLK1 may begin to toggle anytime between when CVDD is at a valid level and the setup time before POR goes high
specified by t6.
3
• Filtered versions of 1.8 V can ramp simultaneously with DVDD18.
• RESETSTAT is driven low once the DVDD18 supply is available.
• All LVCMOS input and bidirectional pins must not be driven or pulled high until DVDD18 is present. Driving an input or bidirectional pin
before DVDD18 is valid could cause damage to the device.
4a
• DVDD15 (1.5 V) supply is ramped up following DVDD18. Although ramping DVDD18 and DVDD15 simultaneously is permitted, the
voltage for DVDD15 must never exceed DVDD18.
4b
• RESET may be driven high any time after DVDD18 is at a valid level. In a POR-controlled boot, RESET must be high before POR is driven
high.
5
• POR must continue to remain low for at least 100 μs after power has stabilized.
End power stabilization phase
6
• Device initialization requires 500 SYSCLK1 periods after the Power Stabilization Phase. The maximum clock period is 33.33 nsec, so a delay
of an additional 16 μs is required before a rising edge of POR. The clock must be active during the entire 16 μs.
7
• RESETFULL must be held low for at least 24 transitions of the SYSCLK1 after POR has stabilized at a high level.
8
• The rising edge of the RESETFULL will remove the reset to the efuse farm allowing the scan to begin.
• Once device initialization and the efuse farm scan are complete, the RESETSTAT signal is driven high. This delay will be 10000 to 50000
clock cycles.
End device initialization phase
9
• GPIO configuration bits must be valid for at least 12 transitions of the SYSCLK1 before the rising edge of RESETFULL
10
• GPIO configuration bits must be held valid for at least 12 transitions of the SYSCLK1 after the rising edge of RESETFULL
End of Table 7-2
112
TMS320C6670 Peripheral Information and Electrical Specifications
Copyright 2012 Texas Instruments Incorporated
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