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i.MX 6UltraLite Applications Processors for Consumer Products, Rev. 2.2, 05/2017
18 NXP Semiconductors
Modules List
DRAM_VREF When using DDR_VREF with DDR I/O, the nominal reference voltage must be half of the
NVCC_DRAM supply. The user can tie DDR_VREF to a precision external resistor divider. Use a
1k 0.5% resistor to GND and a 1 k 0.5% resistor to NVCC_DRAM. Shunt each resistor with a
closely-mounted 0.1 µF capacitor.
To reduce supply current, a pair of 1.5 k 0.1% resistors can be used. Using resistors with
recommended tolerances ensures the ± 2% DDR_VREF tolerance (per the DDR3 specification) is
maintained when two DDR3 ICs plus the i.MX 6UltraLite are drawing current on the resistor divider.
ZQPAD DRAM calibration resistor 240 1% used as reference during DRAM output buffer driver
calibration should be connected between this pad and GND.
GPANAIO This signal is reserved for NXP manufacturing use only. This output must remain unconnected.
JTAG_nnnn The JTAG interface is summarized in Table 5. Use of external resistors is unnecessary. However,
if external resistors are used, the user must ensure that the on-chip pull-up/down configuration is
followed. For example, do not use an external pull down on an input that has on-chip pull-up.
JTAG_TDO is configured with a keeper circuit such that the non-connected condition is eliminated
if an external pull resistor is not present. An external pull resistor on JTAG_TDO is detrimental and
should be avoided.
JTAG_MOD is referenced as SJC_MOD in the i.MX 6UltraLite reference manual. Both names refer
to the same signal. JTAG_MOD must be externally connected to GND for normal operation.
Termination to GND through an external pull-down resistor (such as 1 k) is allowed. JTAG_MOD
set to hi configures the JTAG interface to mode compliant with IEEE1149.1 standard. JTAG_MOD
set to low configures the JTAG interface for common SW debug adding all the system TAPs to the
chain.
NC These signals are No Connect (NC) and should be floated by the user.
POR_B This cold reset negative logic input resets all modules and logic in the IC.
May be used in addition to internally generated power on reset signal (logical AND, both internal
and external signals are considered active low).
ONOFF ONOFF can be configured in debounce, off to on time, and max time-out configurations. The
debounce and off to on time configurations supports 0, 50, 100 and 500 ms. Debounce is used to
generate the power off interrupt. While in the ON state, if ONOFF button is pressed longer than the
debounce time, the power off interrupt is generated. Off to on time supports the time it takes to
request power on after a configured button press time has been reached. While in the OFF state,
if ONOFF button is pressed longer than the off to on time, the state will transition from OFF to ON.
Max time-out configuration supports 5, 10, 15 seconds and disable. Max time-out configuration
supports the time it takes to request power down after ONOFF button has been pressed for the
defined time.
TEST_MODE TEST_MODE is for NXP factory use. The user must tie this pin directly to GND.
Table 5. JTAG Controller Interface Summary
JTAG I/O Type On-chip Termination
JTAG_TCK Input 47 kpull-up
JTAG_TMS Input 47 kpull-up
JTAG_TDI Input 47 kpull-up
JTAG_TDO 3-state output Keeper
Table 4. Special Signal Considerations (continued)
Signal Name Remarks
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