32-bit ARM core microprocessor chip PUC2030A and its application

The 32-bit RISC (Reduced Instruction Set Computer CPU) core (ARM core for short) designed by the British ARM company has significant advantages such as low power consumption and low cost. It currently occupies more than 75% of the 32-bit embedded product market. The ARM series chips are chips based on the ARM core developed by various semiconductor manufacturers. Currently, there are more than 100 international companies designing and producing ARM chips. Domestic companies such as ZTE Integrated Circuit and Huahong have also purchased ARM's cores for the design of communication chips and encryption IC cards.

PUC3030A is a high-performance, low-power microprocessor based on 32-bit ARM core developed by Micronas of Germany. It adopts ARM7TDMI core, internally integrates USB1.1 interface controller, RTC is a real-time clock with calendar and alarm functions, internal watchdog circuit, power management, encryption controller, 256K bytes FLASH, 56K bytes SRAM, etc. In many application fields, its system cost is much lower than the solution of using 8051 plus expansion chip. Since Micronas and its third-party design studio provide numerous program libraries, and ARM's ADS1.2 integrated development environment supports C and C++, its software development is also very easy. Therefore, PUC3030A will be one of the choices for many electronic product solutions.

1 Structural characteristics and performance indicators of PUC3030A

The internal functional block diagram of PUC3030A is shown in Figure 1.

PUC3030A has a 64MHz ARM7TDMI 32-bit microprocessor with about 60MIPS. It runs in small mode and can process MP3, AAC and other digital audio decoding and voice encoding and decoding. It has the function of completing certain data processing and analysis. PUC3030A has a built-in 48KB general SRAM and 256KB Flash RAM. It also has a memory protection unit and an encryption controller, which makes it have good program and data confidentiality.

The PUC3030A has an internal PLL and power controller, which can provide an internal operating frequency of 64MHz using a 6MHz external crystal, and supports four modes: operation, idle, sleep, and shutdown.

The USB1.1 interface of PUC3030A supports control transfer, block transfer, interrupt transfer and isochronous transfer. Supporting isochronous transfer is a major feature of the USB interface of PUC3030A, which is a function not supported by the embedded USB controllers of most other CPUs. This function can support USB audio and real-time data transmission. Its USB interface has 8KB FIFO, which is also not available in the embedded USB controllers of most other CPUs, and even has more USB data cache space than many dedicated USB control chips.

PUC3030A has a flexibly configurable interrupt controller. Each GPIO can be set to FIQ or IRQ interrupt, and the interrupt trigger mode of each GPIO can be set to four trigger modes: high level trigger, low level trigger, rising edge trigger, and falling edge trigger. This allows the processing of low-speed signals such as thumbwheels, infrared receivers, and keyboard scanning to run completely in the background program without occupying CPU time for scanning and detection.

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In addition, PUC3030A also has I2C master/slave interface, 66 GPIO, 5 synchronous serial ports, the maximum bit rate of master mode is 24M, the maximum bit rate of slave mode is 16M, and it supports SPI and I2S. Multiple synchronous serial ports make PUC3030A particularly suitable for multi-channel USB audio products, LED multi-screen display systems, and multi-channel data acquisition and control systems. PUC3030A's two full-function serial ports support high-speed infrared data transmission (IrDA). It also has three 32-bit timers/counters, an internal watchdog timer, and an RTC real-time clock with calendar and alarm functions. BGA81 packaged chips do not have this function.

PUC3030A has a JTAG debugging interface, supports JTAG debugging development tools such as Multi-ICE, Trace32 and Jeeni, and development software such as ADS and SDT2.5, providing a good development environment.

Because PUC3030A has the above-mentioned excellent performance, it even has a cost advantage over the 51 series chips in many application fields. This is because: for general applications, if the 51 chip is used, it is usually necessary to expand 1 SRAM chip, 1 RTC chip, 1 Flash chip, 2 8255 I/O expansion circuits, 1 USB control chip, and 1 watchdog circuit; in addition to the fact that the computing processing speed is much lower than that of the PUC3030A chip, the cost of the 51 solution is much higher than that of the PUC3030A; due to the problems of more wiring and large PCB board area, the circuit reliability of the 51 solution is much lower than that of the single-chip solution using PUC3030A.

PUC3030A currently provides two package types: PQFP100 and LFBGA81. The package size of PQFP100 is 23.2mm×17.2mm, and the package size of LFBGA81 is 9mm×9mm. The latter lacks RTC function and has fewer GPIOs than the former, which is suitable for occasions with particularly small PCB area.

2 PUC3030A has competitive application areas

2.1 Portable MP3 player with USB function

Since PUC3030A supports multiple Flash chips and Flash cards such as Nand Flash, MMC, SDC, CF card, and can support hard disks through GPIO analog bus, it is most suitable for developing portable MP3 players with USB flash drive function.

PUC3030A uses ARM core to access and decode MP3 data. ARM provides a decoding library, which Micronas transplants to PUC3030A. The operating system uses a real-time operating system designed by Micronas specifically for portable MP3 players, which is provided in the form of a library file. Therefore, users only need to modify the corresponding keyboard display program to complete the product design, which greatly shortens the user's development cycle and reduces the investment in human resources.

2.2 Digital voice recorders that support long-term recording

Since PUC3030A supports multiple voice compression formats, if PUC3030A is used as a data codec processor and its built-in USB1.1 interface is used as a data transmission interface, a digital voice recorder that supports long-term recording can be constructed by simply connecting a low-cost voice ADC chip and a large-capacity Flash or MMC card. PUC3030A has a built-in RTC that can automatically record the time information of each recording.

2.3 Portable Data Acquisition System Based on USB1.1

Since PUC3030A has transmission control and data processing functions suitable for portable data acquisition systems, when powered by USB bus, only external ADC/DAC and power management chip are needed to form a complete USB data acquisition system. Moreover, since PUC3030A has the ability of real-time lossless data compression, in some applications, such as audio and image data acquisition systems with large data volume and high data compressibility ratio, high-fidelity transmission can be achieved under the low-cost USB1.1 standard.

2.4 Handheld Water Meter Reading System

Before the launch of PUC3030A, the handheld water meter reading system developed by the author used Samsung's S3B44X0 chip, which required an external expansion of a USB interface chip USBN9603, a BootRom chip 29C040, and an external SDRAM for providing program running space. After switching to PUC3030A, since PUC3030A has the functions of the above four chips, it can be replaced by PUC3030A. This greatly reduces the PCB board area, simplifies the wiring work, and significantly improves the reliability of the system. In addition, the system power consumption of PUC3030A is very low, which is especially suitable for battery-powered handheld instruments.

2.5 Tax Control Cash Register

Because PUC3030A has good program and data encryption functions and powerful data processing capabilities, it can run databases. In addition, its internal RTC clock can provide a time record of each payment received, and two full-function (including RXD, CTS, DSR, DCD, RTS, DTR, RI, TXD) UART interfaces can be easily connected to various barcode readers, magnetic card readers, IC card readers, Modems and other devices.

2.6 USB barcode reader/magnetic card reader/smart card reader/writer and fingerprint door lock/attendance machine

PUC3030A has built-in USB interface and RTC, and has good program and data encryption functions, and low system power consumption. It can form a single-chip barcode reader/magnetic card reader/smart card reader/writer and fingerprint recognition door lock/attendance machine powered by USB bus, no longer requiring external power transformer and serial port line, etc., easy to install and use. The internal RTC can provide time information for each record.

2.7 LED multi-screen display system

LED multi-screen display systems are widely used in airports, stations, docks and other places. The high-speed processing function and up to 5 high-speed SPI interfaces of PUC3030A make it particularly suitable for LED multi-screen display systems. Traditional LED display screens basically use 8051 8-bit processors plus many expansion chips to form a control system. Taking the most common LED display products as an example, the following compares the solution using PUC3030A and the solution using 51 chip plus expansion chip, as shown in Table 1.

Table 1 Comparison between the solution using PUC3030A and the solution using 51 chip plus expansion chip

In addition to the above applications, PUC3030A can also be used in many other fields, especially in applications that require resources such as USB interface, Flash, RTC, multiple synchronous serial ports, and multiple asynchronous serial ports.