MPR083 datasheet(35/56 Pages) FREESCALE

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Embedded Software Description

Blood Pressure Monitor Design Reference Manual, Rev. 0

Freescale Semiconductor

4-5

To generate the audio, the system uses files stored in the MRAM. These are raw audio files using an 8-bit

sample size with an 8 kHz sampling rate. This sampling rate provides audio with about the same quality

as a telephone. It is important to note that this process can be done at a much higher sampling rate that will

generate full audio. The only change required is for the system to have enough memory to be able to store

the larger audio files.

4.4.7

ZigBee Communication

ZigBee communication on the blood pressure monitor is done through an SPI interface to the MC13202

and six separate I/O ports, including the IRQ pin. The IRQ pin signals when the transceiver has

information that it needs to send to the MCU. The transmission of measured data through ZigBee is done

within the OLED state machine whenever the system is displaying measured data. The state machine will

check to see if ZigBee communication is enabled — if so, it will then place the systolic pressure in the

ZigBee transmission buffer, send that buffer through the SPI to the transceiver, then ask the transceiver to

transmit the buffer. This procedure is then repeated for the diastolic pressure and pulse rate that were taken

at the same time. Due to the fact that all ZigBee communications are initiated by the blood pressure

monitor, whenever the system is not sending messages the transceiver is disabled, as well as all peripherals

related to the transceiver for the MCU.

MPR083 датащи(PDF) 35 Page - Freescale Semiconductor, Inc