NXP Semiconductors
UM11227
NTM88 family of tire pressure monitor sensors
UM11227 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2020. All rights reserved.
User manual Rev. 6 — 24 April 2020
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as power is applied to the supply pins. The contents of the parameter registers behave
like RAM and are unaffected by any reset. Parameter registers may be used to store
temporary or history data during the times that the MCU is in any of the STOP modes.
The parameter register at $008F is used by the firmware for interrupt flags.
Table 156. Parameter registers (PARAM0 to PARAM31) (addresses $0050 - $006F)
Bit 7 6 5 4 3 2 1 0
R
W
bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
Table 157. Parameter registers (PARAM32 to PARAM63) (addresses $0070 - $008F)
Bit 7 6 5 4 3 2 1 0
R
W
bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
10.21 Random access memory (RAM0 to RAM511)
The 512 bytes of RAM registers are located at address $0090 through $028F. The
locations in RAM from $0090 to $00FF can be accessed using the more efficient
direct addressing mode, and any single bit in this area can be accessed with the bit-
manipulation instructions (BCLR, BSET, BRCLR, and BRSET). Locating the most
frequently accessed program variables in this area of RAM is preferred.
The RAM retains data when the MCU is in low-power WAIT or STOP4 modes. At power-
on or after wake-up from STOP1, the contents of RAM will not be initialized. RAM data
is unaffected by any reset provided that the supply voltage does not drop below the
minimum value for RAM retention (VRAM).
When security is enabled, the RAM is considered a secure memory resource and is not
accessible through BDM or through code executing from non-secure memory. None of
the RAM locations are used directly by the firmware. The firmware routines utilize RAM
only through stack operations; and the user needs to be aware of stack depth required by
each routine as described in the CodeWarrior project files.
Table 158. Random access memory registers (RAM0 to RAM255) (addresses $0090 - $00FF)
Bit 7 6 5 4 3 2 1 0
R
W
bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
Table 159. Parameter registers (RAM256 to RAM511) (addresses $0100 - $028F)
Bit 7 6 5 4 3 2 1 0
R
W
bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
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