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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SPI may be enabled by either of two methods:
1. MCU application software write to ‘1’ the SPIEN control bit at address $1802
2. At power application, an external host holding the PTA0 pin low for greater than the
time t
SPI_EN
Care must be taken by the user application to assure the SPI is not disabled by writing
'0' to SPIEN bit, or by entering a stop mode, during an ongoing transmission. SPI can be
disabled when SS_B signal is in the inactive state, or high.
10.19 Sensor measurement interface (SMI) module
The sensor measurement interface (SMI) module samples, filters, and scales the
transducer signals into an analog signal suitable for input to the ADC module. The SMI
can be controlled to select the desired transducer channel, filter characteristics, and gain
settings.
The SMI has two operating modes available to users:
• Standby, meaning powered but not measuring
• Measurement mode
The standby mode is defined by the configuration of the following control bits:
• SMIEN bit set to 0
• SMIF bit is = 0
• SEN bit is set to 0
• SCAP bit is set to 0
• SST[2:0] bits are set to 0 0 0
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