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Important announcement about TI Speech product line changes
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Speech Design Considerations
Low Power Precautions
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Low Power Precautions for TI Speech Synthesis Processors
The MSP50x3X family has the ability to be placed in a low power sleep mode in which the current drain is very close to zero. The following precautions should be taken to ensure that no excess current drain occurs:
- Any unused I/O terminals should be tied high or low. Floating I/O terminals may cause leakage current.
- The MSP50P34 has 24 I/O terminals. Only 10 of these terminals are bonded out when the device is packaged in the 16 pin package. To prevent leakage current, these I/O terminals should be biased high or low through software. The software should program bits 2 through 7 of the B port and all of the C port to either be active pullup outputs or internal pullup inputs (see table 2.4 in the MSP50C3X Mixed Signal Processor User's Guide).
- When the internal clock mask option is used, the OSC pin should be tied to Vss.
- The A6 and B0 pins on the MSP50P34 should be biased either high or low through a resistor to minimize leakage when the INIT pin is held low. The MSP50P34 will still exhibit a few microamps of leakage after all precautions are made.
The TSP50C0x/1x family of devices set the I/O pins to a high-
impedance input state following a SETOFF instruction. This is not true on the MSP50x3x family. I/O terminals retain their last programmed state. This may result in current draw through external circuitry if this is not comprehended in the design or software.
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