Attraction voice guides mainly include the following: one is the navigation information of the working satellite by the user terminal of the positioning system (GPS), thereby solving the latitude and longitude information of the vehicle, thereby calculating the real-time coordinates, and puts it with the attraction coordinates Compare, when the vehicle enters the attraction, it is not necessary to manually intervene, the system automatically broadcasts the attraction voice information; the other is to count the corner pulse of the wheel axle, and the count value and preset value are compared to determine play. At the moment, the purpose of accurately playing the attraction voice information; the third solution is to utilize the wireless RF identification technology, set an ID-based RF transmitter within each of each of the attractions, using a batch work mode transmitted signal, when the tourist train is coming to the attraction At the time, the in-vehicle system receives the RF transmitter signal and decodes the ID number of the attraction, and the system is controlled automatically playing the corresponding number of attractions. Due to the complexity of the natural environment, it is difficult to meet the system requirements; the second way is simple and reliable, but there is an uncertainty in the operation direction of the travel rail vehicle, its relative position round-trip, the system is low, and the complexity is high. . This paper adopts the third solution to achieve a sponsorsport automatic navigation system.
This paper first introduces the overall structure of the system, and then gives the specific design of the main functional modules of the system, and focus on the SPI communication control and implementation technology between the STM32F103RBT6 chip and the voice chip ISD4004 based on the ARM3 core. Design implementation results.
It gives a conclusion that has a certain engineering application reference value.
1 system overall design
The structural principle of this system is shown in Figure 1. This design uses the characteristics of tourist train tracks, and the RFID of the fixed ID is pre-installed along the attractions along the track, considering the action distance, data communication mode, reliability, service life, and maintenance cost, select the product 433 MHz active label GAO C124061. It stores ID word length 32 B. Since the possibility of collision is extremely low in the field natural environment, the RFID reader only needs to properly and reliably obtain the Id value of the RFID, corresponding to the fixed attraction, to trigger the interrupt, start playing the voice information of the attraction.
In Fig. 1, the MCU uses the STM32F103RBT6 chip, which is based on ARM Cortex-M3 core high performance, low cost, low power embedded application MCU. This design is the reason why this design is to value its price ratio: 128 kb flash, 20 kb SRAM, 2 SPI, 3 serial port, 1 USB, 1 CAN, 2 12-bit ADC, RTC, 51 available I / Osa foot and other series of performance characteristics, fully meet the performance requirements of this system. Summarize, STM32 has a low price, strong function, simple use, and convenient development. ISD4004 is a voice book memory chip that can be randomly entered and voice played according to external control and peripheral circuit assist. The system MCU obtains the fixed ID of the RFID along the travel train through the RFID reader. According to the start address information of the preset voice data storage location corresponding to the ID number, the STV voice selection is automatically played by controlling the SPI port of the ISD4004.
2 main module circuit design
2.1 ISD4004 Control Circuit Design
ISD4004 series voice chip operating voltage is +3 V, single-chip recording time 8 ~ 16 min, sound quality. The chip uses CMOS technology, contains clock, anti-aliasing filters, smoothing filters, audio amplifiers, automatic stainless and high density multi-level non-volatile memory arrays. Chip design is based on all operations must be controlled by microcontroller, and the operational command can be sent through a serial communication interface (SPI). The chip uses a multi-level direct analog storage technology. Each sampling value is stored directly in the in-chip non-volatile memory, so it can be very real, naturally reproduced, music, tone and effect, avoid general solid recording circuit. Quantified noise and metal sound caused by quantitative and compression. The chip ISD4004 internal structure and main pin functions are shown in Figure 2.
The ISD4004 internal device control unit setting is very convenient to communicate with the SPI of the STM32 sequence chip. Increasing STM32 multiple I / O ports to achieve multiple ISD4004 extensions as a slice selected to correspond to the voice chip. The interface circuit of the STM32 and the plurality of ISD4004 is shown in Figure 3.
The STM32 and ISD4004 communicate via the SPI module, both MISI, MISO pin correspond to each other, implement data serial transmission between STM32 and ISD4004 (Before the MSB bit). Communication is always initiated by the master STM32. STM32 sends data to ISD4004 via MOSI feet, ISD4004 retransmit data to STM32 via MISO pin.
The data output and data input of the full duplex communication are synchronized with the same clock signal; the clock signal is provided by the main device STM32 via the SCK pin.
After the expansion is a plurality of speech chips, the storage space of the voice information is greatly increased, which is easy to expand the voice information of the attraction.
2.2 Speech Realling Control Circuit Design
The speech booklet control circuit is shown in Figure 4. Control the series tuning tube Q3 or switch Q1 by the I / O control of the MCU, realize the system amplification or recording. When the I / O end outputs high-speed timing, the sound is realized, and the output is displayed low.
2.3 RFID card reader interface circuit
The RFID card reader module uses the high integrated ISO14443A read card MFRC500 of Philips. The RFID card reader is a relatively independent functional module that outputs the interrupt status information and serial ports with an external connection. Therefore, the system uses the SPI2 interface of the STM32F103RBT6 to realize data communication between the RFID card reader interface, thereby automatically obtaining the attraction location information to control the playback of the corresponding attractions Guide voice. The reader interrupt state is directly connected to the PD port I / O pin of STM32F103; SPI2 interface circuit is similar to Figure 3.
3 main function software design
3.1 Software initialization
3.1.1 Enablement of the peripheral clock
The peripheral clocks involved in this design can enable registers through the APB2 peripheral clock. When the peripheral clock is not enabled, the software cannot read the value of the peripheral register, and the returned value is always 0. The PA port used in the design, the PB port, the PD port of the PD port, respectively through the APB2ENR registers, respectively, 5 bits set, the clock of the SPI1 is set through the 12th bit of APB2ENR.
3.1.2 Initialization of I / O port
The I / O port involved in this design includes: PA.3, PB.0, PB.0, which is used for control panel, need to be set to start output mode; used to implement PA.15 (recording key) of button control, PA.0 (Forced stop keys), etc., it is necessary to set to pull the input mode; used to implement the PA.5, PA.6, PA.7 port of SPI communication, and they correspond to SCK, MISO, MOSI port of SPI1, and should be set by software. The three ports are multiplex I / O ports, second function; PA.8 and PD.2 are set to pull-up input mode when detecting the end of the play.
3.1.3 Initialization of external interrupt
The main completion of the external interrupt initialization is to set the corresponding relationship between the I / O port and the interrupt line, turn on the online interrupt / event corresponding to the I / O port, and the trigger condition of the setting interrupt, configure interrupt group and enable interrupt. . In this design, the interrupt trigger condition corresponding to the PA.0 port connected to the mandatory stop button is set to the rising edge trigger, the corresponding interrupt priority; the other button connection I / O port corresponding interrupt trigger condition is set to the falling edge Trigger. Assign all interruptions to the second group, setting all the priorities of all buttons, and the priority of the preemption is different. Among them, the I / O port connected to several playback keys is shared with an interrupt service program, that is, the interrupts on multiple interrupt lines share an interrupt service function, and the signal enters the interrupt in the interrupt service program. Perform a distinction (by interrupting the level of input I / O port), again processing.
3.1.4 Initialization of the SPI module
In this design, by setting the SPI1 module into full-duplex mode, software NSS management, host mode, 8 B MSB data format, and puts the baud rate of SPI1 into (281.25 kHz, for system clock) 256 Dividend), which is important that the SPI module outputs serial synchronization clock polarity and phase configuration, the SPI master module and the external device clock phase and polarity of the communication should be consistent. , Send 0xFF boot transmission.
According to the SPI bus transmission timing and SPI operation timing relationship under different phases of the ISD4004, the SPI communication between STM32 and ISD4004 is required to set it to 1 to 1.
3.2 SPI control function software implementation
3.2.1 SPI1 Read Writing Function
When reading data, the received data is stored in an internal receiving buffer; when writing data, the data will be stored in an internal transmit buffer before being transmitted. The read operation of the SPI_DR register will return the content of the receiving buffer; the data written to the SPI_DR register will be written into the send buffer.
The SPI_SR is a 16-bit state register. Its bit is RXNE, which is 0, the receiving buffer is empty, and the reception buffer is non-empty; the SPI_SR is low as TXE, which is 0 description transmission buffer non-empty, 1 Then the transmission buffer is empty. Constantly querying whether the transmission / reception buffer is empty, and then the orderly sends and receive data.
3.2.2 Send instruction function
First, the voice chip ISD4004 has the following operation rules:
(1) Serial section interface, SPI protocol Sets the microcontroller's SPI shift register in SCLK falling action, and the MOSI pin is latched in the clock rising edge data, and the data is sent to the MISO pin in the falling edge.
(2) The power can be started after the device delay TPUD (8 kHz sampling, about 25 ms) can only be started. Therefore, after the user has finished the upper electrical order, the next operational instruction must be issued.
For example, from 00, you should follow the following timing:
1 Send Power UP command;
2 Waiting for TPUD (on-board delay);
3 Seet play commands for the address value of 00;
4 Send a play command.
The device will play a play from the 00 address. When an eOM appears, immediately interrupt, stop the play.
If you are recording from 00, press the following timing:
1 Send Power Up Directive;
2 Waiting for TPUD (on-board delay);
3 send Power UP command;
Our other product:
