subject: RF and wireless data transmission system SoCnRF9E5 implementation-nRF9E5, RF SoC, data transmission - Communications Industry [print this page] RF and wireless data transmission system SoCnRF9E5 implementation-nRF9E5, RF SoC, data transmission - Communications Industry
Introducing the latest 51-compatible RF SoC (System on Chip) nRF9E5 system framework, the various components, working methods and configuration; of wireless data transmission system of the structure and use of nRF9E5 for wireless data communication protocol design; given hardware schematic diagram and flow chart; summarized nRF9E5 in the wireless data transmission system design advantage.
Introduction NRF9E5 is NordicVLSI company on Feb. 5, 2004 launch of the system-level RF chip, the built-in nRF905433/868/915MHz transceiver, 8051 compatible microcontroller and a 4 input 10-bit 80kSPsA / D converter It is true SoC shown in Figure 1. Built nRF905 transceiver chip transceiver with nRF905 like to work in ShockBurst (automatic processing of the prefix, address and CRC) method. Built-in voltage regulator module, the maximum suppression of noise, the system provides 1.9 ~ 3.6V operating voltage, QFN5 5mm package, the carrier detection. nRF9E5 meet the Federal Communications Commission and the European Telecommunications Standards Institute of the relevant standards. As nRF905 low power consumption, reliable work, so it is suitable for wireless data transmission system.
1 nRF9E5 Features 1.1 nRF9E5 hardware (1) micro-controller NRF9E5 of the chip micro-controller and the standard 8051 compatible with the standard 8051 instruction slightly different timing. The typical difference is: nRF9E5 chip microcontroller instruction cycle is 4 to 20 instruction cycles. Interrupt controller supports five extended interrupt sources: ADC interrupt, SPI interrupt, RADIO1 interrupt, RADIO2 interrupt and wake-up timer interrupt. There are three controller chip same with the 8052 timer. One and the same serial port 8051, you can use Timer 1 and Timer 2 as a baud rate generator asynchronous communication. In addition, expansion of the two data pointers, to facilitate the read data from the XRAM area. Microprocessors in the data RAM 256B and 512B of the ROM. Power-on reset or software reset, the processor automatically ROM boot code. User program is usually under the guidance of the boot from EEROM loaded into a 4KB of RAM, 4KB of RAM that can be used for storing data. NRF9E5 most of the registers and the same standards of 8051, only a few special function registers, such as RADIO (P2), ADCCON, ADCDATAH, ADCDATAL, ADCSTATIC, PWMCON, PWMDUTY, RCAP2L, RCAP2H, CKLFCON so. nRF9E5 in P0, P1 and P2 port 8051 in the register address and the same standards are 0x80, 0x90, 0xA0, but the functions and standards of 8051 to be different.
(2) CKLF clock, RTC wake-up timer, GPIO wake-up and the WTD
NRF9E5 there is a low-frequency clock CKLF, the clock always open. When the crystal began to work, CKLF frequency of 4Hz; crystal does not work, CKLF RC oscillator is a low-power devices, as long as VDD 1.8V, the continuous work. RTC wake-up timer, WTD (watchdog), and GPIO wake-up all work in CKLF frequency, chip power consumption to ensure that the work to complete these three functions. RTC wake-up timer is controlled by a programmable 24-bit down counter, WTD is a 16-bit programmable control down counter. WTD RTC wake-up timer and the cycle of generally 300 s ~ 80ms, default is 1ms. RTC wake-up timer can be GPIO output source, that is, when the RTC wake-up timer overflow occurs when the initialization time, to produce a program output pulse used as GPIO.
(3) SPI interface and A / D converter
SPI (Serial Peripheral Interface) interface pin with MISO (EEPROM of the SDO to receive the data sent), SCK (SCK provided to the EEPROM's clock), MOSI (send data to the EEPROM of the SDI ), EECSN (EEPROM of the CSN to send enable signal). SPI port of the MISO, SCK and MOSI and the P1 port of the low 3 reuse, through the control register to control the function SPI_CTRL replaced between. SPI hardware does not generate any chip select signal can be carried out with GPIO port chip select. Typically, when the power system, SPI and chip 25,320 is connected automatically. When the program load is completed, MISO (P1.2), MOSI (P1.0) may be used for other purposes, such as other SPI devices or GPIO.
NRF9E5 chip with 10-bit ADC, A / D converter reference voltage can be set by software between AREF and 1.22V (internal reference voltage). A / D converter, 4 inputs can be selected by software, channel 0 to 3 can pin AIN0 ~ AIN3 on the corresponding voltage values into digital values, channel 4 is used to nRF9E5 voltage monitoring. A / D converter 10-bit default working on ways to work through the software in six, eight or 12-bit mode.
(4) RF Transceiver NRF9E5 transceiver through an internal parallel port or an internal SPI port to communicate with other modules with the same single-chip radio transceiver nRF905 the same functionality. Transceiver chip MCU via the parallel port or SPI port and the micro-controller communications, data ready, carrier detect and address match signals to a micro-controller and interrupt.
NRF905 work in 433/868/915MHzISM band. Get away from the one transceiver frequency synthesizer, a power amplifier, a regulator Lu and two receivers composition. Output power, channel, and other RF parameters can be of special function register RADIO (0xA0) control program. Firing mode, RF current consumption 11mA, receive mode to 12.5mA. For energy, the transceiver can be programmed on / off.
1.2 nRF9E5 way transceiver Different nRF401 and nRF903, nRF9E5 use the SPI interface between the microcontroller and wireless data transmission module. This part of the 8051 chip in nRF9E5 nRF905 RF transceiver core and between the completion. nRF9E5 8051 chip RF transceiver core with nRF905 completed between. nRF905 8051 chip RF transceiver core with nRF905 completed between. nRF9E5 transceiver work in three ways, ShockBurst receiver (RX) mode, ShockBurst send (TX) mode and idle mode. When the transceiver is in idle mode, the microcontroller is still running.
NRF9E5 use NordicVLSI's ShockBurst features, high-speed data transfer. Agreement with the RF data related to the n-chip by the nRF9E5
