SLAU367P October 2012 – April 2020 MSP430FR5041 , MSP430FR5043 , MSP430FR50431 , MSP430FR5847 , MSP430FR58471 , MSP430FR5848 , MSP430FR5849 , MSP430FR5857 , MSP430FR5858 , MSP430FR5859 , MSP430FR5867 , MSP430FR58671 , MSP430FR5868 , MSP430FR5869 , MSP430FR5870 , MSP430FR5872 , MSP430FR58721 , MSP430FR5887 , MSP430FR5888 , MSP430FR5889 , MSP430FR58891 , MSP430FR5922 , MSP430FR59221 , MSP430FR5947 , MSP430FR59471 , MSP430FR5948 , MSP430FR5949 , MSP430FR5957 , MSP430FR5958 , MSP430FR5959 , MSP430FR5962 , MSP430FR5964 , MSP430FR5967 , MSP430FR5968 , MSP430FR5969 , MSP430FR5969-SP , MSP430FR59691 , MSP430FR5970 , MSP430FR5972 , MSP430FR59721 , MSP430FR5986 , MSP430FR5987 , MSP430FR5988 , MSP430FR5989 , MSP430FR5989-EP , MSP430FR59891 , MSP430FR5992 , MSP430FR5994 , MSP430FR59941 , MSP430FR6005 , MSP430FR6007 , MSP430FR6035 , MSP430FR6037 , MSP430FR60371 , MSP430FR6041 , MSP430FR6043 , MSP430FR60431 , MSP430FR6045 , MSP430FR6047 , MSP430FR60471 , MSP430FR6820 , MSP430FR6822 , MSP430FR68221 , MSP430FR6870 , MSP430FR6872 , MSP430FR68721 , MSP430FR6877 , MSP430FR6879 , MSP430FR68791 , MSP430FR6887 , MSP430FR6888 , MSP430FR6889 , MSP430FR68891 , MSP430FR6920 , MSP430FR6922 , MSP430FR69221 , MSP430FR6927 , MSP430FR69271 , MSP430FR6928 , MSP430FR6970 , MSP430FR6972 , MSP430FR69721 , MSP430FR6977 , MSP430FR6979 , MSP430FR69791 , MSP430FR6987 , MSP430FR6988 , MSP430FR6989 , MSP430FR69891
18.1 Introduction
The USS module is designed for analog-to-digital (ADC) converter based ultrasonic sensing technology in various measurement applications. Figure 18-1 shows the block diagram of the USS module. The USS is a sophisticated system that consists of the following four submodules. USS_A is an extended variant of the original USS module and features SAPH_A instead of the SAPH module. Because USS_A is a superset of USS, USS_A is specifically named only when describing feature that differ between USS and USS_A.
- UUPS: Generates reference voltages, currents, and operation voltage for the USS module, and controls the power-up and power-down sequences of the USS module. See UUPS for details.
- HSPLL: Generates a low-jitter clock (68 MHz to 80 MHz) from the USSXT oscillator for the USS module. See HSPLL for details.
- SAPH (part of USS): Consists of a pulse generator, a low-impedance output driver, an input multiplexer, and an acquisition sequencer. See SAPH for details.
- SAPH_A (part of USS_A): Consists of an extended pulse generator, a low-impedance output driver, an input multiplexer, an acquisition sequencer and external bias terminals. See SAPH_A for details.
- SDHS: High-speed sigma-delta analog-to-digital converter with a dedicated data transfer controller. See SDHS for details
The submodules have different roles, and together they enable high-precision data acquisition for ultrasonic technology in various applications. The USS module has a dedicated power management module, UUPS, which generates operating voltage, reference voltages, and reference currents for other submodules. The USS module also has a dedicated clock module, HSPLL, which generates a very-low-jitter clock (68 MHz to 80 MHz) from the USSXT oscillator. The SAPH or SAPH_A module controls the signal flow including excitation pulse generation through a low-impedance driver (3-4 Ω, typical), internal bias voltages for Tx and Rx sides, and the input multiplexer. The SDHS is a high-speed analog-to-digital converter to sample the input signals and transfer the output data to the target memory location. The Low Energy Accelerator (LEA), if available, processes the data transferred by the SDHS.
The USS module supports three operation modes for data acquisition sequence: auto mode, register mode and ultra low power bias mode.
In auto mode, the entire measurement sequence is automatically controlled by the ASQ block. Control by ASQ enables ultra-low power consumption during the measurement and frees the CPU from data acquisition, so that ultrasonic application software can be executed in parallel with data acquisition with minimum intervention.
In register mode, the measurement sequence is fully controlled by user software. The register mode can be used during development and for special tasks like diagnostics.
In ultra low power bias mode the ASQ sequencer performs an extended power sequence dedicated for the ultra low power utility meter market.
Figure 18-1 USS and USS_A Block Diagram NOTE
Naming convention for register names and bit fields:
ModuleName.RegisterName or ModuleName.RegisterName.BitField