Freescale Semiconductor
MCIMX53SMD Board Hardware User’s Guide, Rev. 0
35
5.3.1
Peripheral Module Logic Voltage Levels
By convention, pins used on the i.MX53 processor to set module logic voltage levels begin with NVCC_*. This
information about i.MX53 processor is important for developers when they are developing projects based on
i.MX53 processor. There are 25 such pins, and practically speaking, they supply the internal pull-up voltages
for pins designated for data output. These 25 pins are explained in
Table 5-3
. Once a voltage level is selected
for a particular module, all pins within that module will use the same voltage level. It is important for the
developer not to try to use an external pull-up to a different voltage level for individual pins. Level shifters
must be used if certain pins need to have different voltage levels to interface with external ICs. If a different
voltage level is used on an external pull-up, one or both of the affected power rails will most likely have a
different voltage level than intended, throughout the design. On a newly designed board that shows
unexpected voltage levels, this may be the first thing to check.
Pin Name
Module
Allowed Values
MCIMX53SMD board
NVCC_EMI_DRAM_1
NVCC_EMI_DRAM_2
NVCC_EMI_DRAM_3
NVCC_EMI_DRAM_4
NVCC_EMI_DRAM_5
External Memory Interface
1.425V - 1.9V
1.5V (Match DDR3 Memory)
NVCC_NANDF
NAND Flash
1.65V - 3.6V
1.8V
NVCC_EIM_MAIN_1
NVCC_EIM_MAIN_2
NVCC_EIM_SEC
External Interface Module
1.65V - 3.6V
3.3V
NVCC_RESET
Reset Logic Levels
1.65V - 3.1V
1.8V (Match PMIC)
NVCC_SD1
SD Card Module 1
1.65V - 3.6V
3.3V (Match SD Cards)
NVCC_SD2
SD Card Module 2
1.65V - 3.6V
3.3V
NVCC_PATA
Parallel ATA
1.65V - 3.6V
3.3V
NVCC_LCD_1
NVCC_LCD_2
LCD Module
1.65V - 3.1V
2.775V
NVCC_CSI
Camera Sensor Interface
1.65V - 3.6V
1.8V
NVCC_FEC
Fast Ethernet Controller
1.65V - 3.6V
3.3V (Match Ethernet PHY)
NVCC_GPIO
General Purpose I/O
1.65V - 3.6V
3.3V
NVCC_JTAG
JTAG Module
1.65V - 3.1V
1.8V
NVCC_KEYPAD
Keypad Port
1.65V - 3.6V
3.3V (Match Audio CODEC)
NVCC_CKIH
Clock Amplifier Circuit
1.65V - 1.95V
1.8V
NVCC_XTAL
24MHz Crystal Supply
2.25V - 2.75V
2.5V
NVCC_SRTC_POW
Secure Real Time Clock
1.1V - 1.3V
1.3V
NVCC_LVDS
Low Voltage Differential Signaling
2.375V - 2.625V
2.5V
NVCC_LVDS_BG
LVDS Band Gap
2.375V - 2.625V
2.5V
Table 5-3.
Module Voltage Supplies
The MCIMX53SMD board has a number of unpopulated pull-up resistors. This is a result of the initial design
being conservative, and the addition of external pull-up resistors to supplement internal i.MX53 pull-up supply
voltage. Subsequent MCIMX53SMD board usage has shown these pull-ups to be unnecessary, so they are
unpopulated.
5.3.2
Boot Mode Operations and Selections
The i.MX53 processor can be directed to boot from:
