Key Components Description and Operation
UG0557 User Guide Revision 4.0
12
The following figure shows the on-board core power measurement circuitry.
Figure 5 •
Core Power Measurement Circuitry
4.2.2
1.2 V Current Sensing for Flash*Freeze Mode
The SmartFusion2 device consumes very less power in Flash*Freeze mode. The voltage across the
sense resistor (0.05
Ω
) must be measured directly using a precision digital multimeter that can read sub-
millivolts. The
TP16
and
TP17
test points can be used to directly measure the voltage across the 1.2 V
sense resistor.
To convert the voltage measured across a sense resistor to power, use the following equation.
Note:
Accuracy is ± 10%.
4.3
Memory Interface
Dedicated I/Os for MSS DDR and fabric DDR are available in the SmartFusion2 device.
4.3.1
DDR3 SDRAM
Four chips with 256 MB DDR3 memory are provided in the SmartFusion2 device as flexible volatile
memory for user applications. Additionally, one chip with 256 MB DDR3 memory is provided for ECC.
You can enable the SECDED feature using ECC. The DDR3 interface is implemented in Bank2.
DDR3 SDRAM specifications for the SmartFusion2 device are as follows.
•
MT46H32M16LF: 32 Meg × 8 × 8 banks
•
Density: 256 MB
•
Clock rate: 800 MHz
•
Data rate: DDR3 - 1600
•
Total capacity: 1 GB across four chips
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9
9
9
73
8
73
73
B
*DLQ
Power
voltage in millivolts
0.05
-----------------------------------------------------------
1.2
=
