Abstract: This article gives an example of applying nRF24E1 in a short-range communication system.
introduction
nRF24E1 is a high-speed 1Mbps monolithic wireless transceiver chip embedded in the core of a high-performance single-chip microcomputer launched by Nordic.
Compared with Bluetooth, nRF24E1 has no complicated communication protocol, is completely transparent to users, and can communicate freely between the same products. More importantly, nRF24E1 is cheaper than Bluetooth products and has a cost advantage. So nRF24E1 is a low-cost radio frequency system-level chip with small size, low power consumption and few peripheral components in the industry.
nRF24E1
The block diagram of nRF24E1 wireless transceiver chip is shown in Figure 1.
The nRF24E1 is embedded in the 2.4GHz wireless core nRF2401, which has a globally open 2.4GHz frequency band and 125 channels, which can meet the needs of multi-frequency and frequency hopping. Integrated enhanced 8051 microprocessor core, 9-channel 10-bit ADC, sampling rate 100kHz, built-in voltage reference, power detection, configurable PWM output, UART asynchronous serial port, SPI synchronous communication serial port; built-in CRC verification and multi-point communication control, suitable for Point-to-multipoint communication.
Use 1.9 ~ 3.6V power supply, few peripheral circuits, all operating parameters such as transmission power and operating frequency are all set by software. All high-frequency components including inductors and oscillators have been integrated into the chip, with good consistency and performance Stable and free from outside influence. Moreover, each chip can set up to 40-bit address through software, and data will be output only when the local address is received (providing an interrupt indication), and programming is very convenient. The built-in CRC error detection and detection hardware circuit and protocol are very convenient for software developers to program. Because there is no need to complete the error detection and calculation by the single chip microcomputer, the difficulty of wireless application development can be reduced.
Using DuoCeiver technology can simultaneously receive two nRF2401 data. The basic principle is that DuoCeiver is a simultaneous dual-channel receiving mode. The nRF24E1 can receive data from two 1 Mbps transmitters (for example: nRF24E1, nRF2401 or nRF2402) separated by 8MHz through an antenna interface. The output of the two data channels is fed back to two sets of independent interface pins:
Data channel 1: CLK1, DATA, DR1
Data channel 2: CLK2, DOUT2, DR
Figure 1 nRF24E1 block diagram
Figure 2 DuoCeivertm simultaneous dual receive channel
The DuoCeiver technology provides RX with two independent dedicated digital channels, replacing the requirements for two separate receiving systems. The DuoCeiver shown in Figure 2 has dual receive channels simultaneously. The frequency of digital channel 2 is 8 MHz higher than that of digital channel 1 to ensure normal reception.
nRF24E1 also has a high rate of 1Mbps, which is higher than Bluetooth and has high data throughput. Built-in WTD watchdog with data time slot and data clock recovery.
Application circuit
Figure 3 nRF24E1 RF circuit connected to a single-ended 50W antenna
The RF circuit of nRF24E1 connected to a single-ended 50W antenna is shown in Figure 3.
This circuit diagram contains all the circuits needed to implement nRF24E1 in a short-range communication system. All digital I / O signals and A / D inputs around the wiring diagram can be connected to the peripheral parts used by the user. The program code of serial EEPROM required by nRF24E1 is included in the circuit. EEPROM is a standard 2XX320 SPI type. The circuit has its own power supply and grounding. The power supply of this part of the application circuit should be separated from any high-current peripheral power supply filtering. The single-ended 50W antenna uses a different single-ended matching network.
The following points should be noted in practical applications:
The available frequency band is determined by local adjustment;
The crystal frequency should be selected from the different values ​​specified in the five configuration tables of 4, 8, 12, 16 and 20MHz. Usually 16MHz is used when the data rate is 1Mbps;
The data rate can only be 250kbps or 1000kbps;
The load impedance of the non-embedded antenna is 400W. â–
references
1. Nordic VLSI. 2.4Ghz RF transceiver with embedded 8051 compaTIble microcontroller and 9 input, 10 bit ADC. 2003.7
2. Nordic VLSI. NRF24E1 and nRF24E2 RF layouts. 2003.5
introduction
nRF24E1 is a high-speed 1Mbps monolithic wireless transceiver chip embedded in the core of a high-performance single-chip microcomputer launched by Nordic.
Compared with Bluetooth, nRF24E1 has no complicated communication protocol, is completely transparent to users, and can communicate freely between the same products. More importantly, nRF24E1 is cheaper than Bluetooth products and has a cost advantage. So nRF24E1 is a low-cost radio frequency system-level chip with small size, low power consumption and few peripheral components in the industry.
nRF24E1
The block diagram of nRF24E1 wireless transceiver chip is shown in Figure 1.
The nRF24E1 is embedded in the 2.4GHz wireless core nRF2401, which has a globally open 2.4GHz frequency band and 125 channels, which can meet the needs of multi-frequency and frequency hopping. Integrated enhanced 8051 microprocessor core, 9-channel 10-bit ADC, sampling rate 100kHz, built-in voltage reference, power detection, configurable PWM output, UART asynchronous serial port, SPI synchronous communication serial port; built-in CRC verification and multi-point communication control, suitable for Point-to-multipoint communication.
Use 1.9 ~ 3.6V power supply, few peripheral circuits, all operating parameters such as transmission power and operating frequency are all set by software. All high-frequency components including inductors and oscillators have been integrated into the chip, with good consistency and performance Stable and free from outside influence. Moreover, each chip can set up to 40-bit address through software, and data will be output only when the local address is received (providing an interrupt indication), and programming is very convenient. The built-in CRC error detection and detection hardware circuit and protocol are very convenient for software developers to program. Because there is no need to complete the error detection and calculation by the single chip microcomputer, the difficulty of wireless application development can be reduced.
Using DuoCeiver technology can simultaneously receive two nRF2401 data. The basic principle is that DuoCeiver is a simultaneous dual-channel receiving mode. The nRF24E1 can receive data from two 1 Mbps transmitters (for example: nRF24E1, nRF2401 or nRF2402) separated by 8MHz through an antenna interface. The output of the two data channels is fed back to two sets of independent interface pins:
Data channel 1: CLK1, DATA, DR1
Data channel 2: CLK2, DOUT2, DR
Figure 1 nRF24E1 block diagram
Figure 2 DuoCeivertm simultaneous dual receive channel
The DuoCeiver technology provides RX with two independent dedicated digital channels, replacing the requirements for two separate receiving systems. The DuoCeiver shown in Figure 2 has dual receive channels simultaneously. The frequency of digital channel 2 is 8 MHz higher than that of digital channel 1 to ensure normal reception.
nRF24E1 also has a high rate of 1Mbps, which is higher than Bluetooth and has high data throughput. Built-in WTD watchdog with data time slot and data clock recovery.
Application circuit
Figure 3 nRF24E1 RF circuit connected to a single-ended 50W antenna
The RF circuit of nRF24E1 connected to a single-ended 50W antenna is shown in Figure 3.
This circuit diagram contains all the circuits needed to implement nRF24E1 in a short-range communication system. All digital I / O signals and A / D inputs around the wiring diagram can be connected to the peripheral parts used by the user. The program code of serial EEPROM required by nRF24E1 is included in the circuit. EEPROM is a standard 2XX320 SPI type. The circuit has its own power supply and grounding. The power supply of this part of the application circuit should be separated from any high-current peripheral power supply filtering. The single-ended 50W antenna uses a different single-ended matching network.
The following points should be noted in practical applications:
The available frequency band is determined by local adjustment;
The crystal frequency should be selected from the different values ​​specified in the five configuration tables of 4, 8, 12, 16 and 20MHz. Usually 16MHz is used when the data rate is 1Mbps;
The data rate can only be 250kbps or 1000kbps;
The load impedance of the non-embedded antenna is 400W. â–
references
1. Nordic VLSI. 2.4Ghz RF transceiver with embedded 8051 compaTIble microcontroller and 9 input, 10 bit ADC. 2003.7
2. Nordic VLSI. NRF24E1 and nRF24E2 RF layouts. 2003.5
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