Texas Instruments MSP430FG4618/F2013, Руководство пользователя

Страница: 6 / 18

Sampling frequency
Analog in
Analog out
Digital in
Output jack
Microphone
First-order
active high-
pass filter
using OA0
12-bit ADC
Data
processing
12-bit DAC
Second-order
active low-
pass filter
using OA1
Active
voltage
follower
using OA1
Hardware Overview
www.ti.com
6 SLAU213B – March 2007 – Revised August 2018
Submit Documentation Feedback
Copyright © 2007–2018, Texas Instruments Incorporated
MSP430FG4618/F2013 Experimenter Board (MSP ‑ EXP430FG4618)
6.2.2 RS-232
For a serial interface to a PC, the MSP430FG4618 supports the standard RS-232 9-pin interface through
its USCI peripheral configured in UART mode. Software can configure standard baud rates for
transmission and reception.
6.2.3 I
2
C and SPI
The MSP430FG4618 and the MSP430F2013 support I
2
C and SPI protocols through the USCI and the USI
peripherals for inter-processor communication. The links can be disconnected in hardware to use these
peripherals for other communication purposes.
6.3 Analog Signal Chain
The experimenter board can form a complete analog signal chain using the MSP430FG4618. This board
can be used for numerous audio applications. The board can record and play audio signals without the
use of additional external components.
Figure 4. Analog Signal Chain of MSP430 MCU
6.3.1 Microphone
The microphone is connected to the MSP430FG4618 and may be used for various applications. The
microphone is enabled or disabled through a port pin connected to the MSP430FG4618.
6.3.2 Analog Filters
An active first-order high-pass filter (HPF) with a cut-off frequency of approximately 340 Hz follows the
microphone to eliminate extremely low input frequencies. An optional second-order Sallen-Key active low-
pass filter (LPF) with a cut-off frequency of approximately 4 kHz removes the high-frequency noise on the
analog output of the 12-bit DAC.
Figure 5 shows the filter setup. These filters use the integrated op-amps
of the MSP430 MCU. The op-amps OA0 and OA1 facilitate the filtering processes. The gray blocks in
Figure 5 are elements that are internal to the MSP430FG4618.