Datasheet
i.MX RT1015 Crossover Processors Data Sheet for Consumer Products, Rev. 0.1, 03/2019
12 NXP Semiconductors
Modules list
3.1 Special signal considerations
Table 3 lists special signal considerations for the i.MX RT1015 processors. The signal names are listed in
alphabetical order.
The package contact assignments can be found in Section 6, Package information and contact
assignments. Signal descriptions are provided in the i.MX RT1015 Reference Manual (IMXRT1015RM).
Table 3. Special signal considerations
Signal name Remarks
DCDC_PSWITCH PAD is in DCDC_IN domain and connected the ground to bypass DCDC.
To enable DCDC function, assert to DCDC_IN with at least 1ms delay for DCDC_IN rising edge.
RTC_XTALI/RTC_XTALO If the user wishes to configure RTC_XTALI and RTC_XTALO as an RTC oscillator, a 32.768 kHz
crystal, (100 k ESR, 10 pF load) should be connected between RTC_XTALI and RTC_XTALO.
Keep in mind the capacitors implemented on either side of the crystal are about twice the crystal
load capacitor. To hit the exact oscillation frequency, the board capacitors need to be reduced to
account for board and chip parasitics. The integrated oscillation amplifier is self biasing, but
relatively weak. Care must be taken to limit parasitic leakage from RTC_XTALI and RTC_XTALO
to either power or ground (>100 M). This will debias the amplifier and cause a reduction of
startup margin. Typically RTC_XTALI and RTC_XTALO should bias to approximately 0.5 V.
If it is desired to feed an external low frequency clock into RTC_XTALI the RTC_XTALO pin must
remain unconnected or driven with a complimentary signal. The logic level of this forcing clock
should not exceed VDD_SNVS_CAP level and the frequency should be <100 kHz under typical
conditions.
In case when high accuracy real time clock are not required system may use internal low
frequency ring oscillator. It is recommended to connect RTC_XTALI to GND and keep
RTC_XTALO unconnected.
XTALI/XTALO A 24.0 MHz crystal should be connected between XTALI and XTALO. External load capacitance
value depends on the typical load capacitance of crystal used and PCB design.
The crystal must be rated for a maximum drive level of 250 W. An ESR (equivalent series
resistance) of typical 80 is recommended. NXP SDK software requires 24 MHz on
XTALI/XTALO.
The crystal can be eliminated if an external 24 MHz oscillator is available in the system. In this
case, XTALO must be directly driven by the external oscillator and XTALI mounted with 18 pF
capacitor. The logic level of this forcing clock cannot exceed NVCC_PLL level.
If this clock is used as a reference for USB, then there are strict frequency tolerance and jitter
requirements. See OSC24M chapter and relevant interface specifications chapters for details.
GPANAIO This signal is reserved for NXP manufacturing use only. This output must remain unconnected.
JTAG_nnnn The JTAG interface is summarized in Tabl e 4. 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 RT1015 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 disconnected by the user.