 Hello, and welcome to this presentation of the STM32WL5 sub gigahertz radio controller. The sub gigahertz radio operates in the ISM150-960MHz band, providing low-ra, frequency shift keying, minimum shift keying, Gaussian frequency shift keying, Gaussian minimum shift keying, and binary phase shift keying modulations. The radio complies with the European Telecommunications Standards Act, European Norm 300, 220, 301.13, and 301.166, Federal Communications Commission Code of Federal Regulation 47, Part 15, 24, 90, and 101, and Association of Radio Industries and Businesses Standard T30, T67, and T108. It enables the building of systems for the following standards, low-row wireless area network, SIGFOX, etc., and proprietary protocols. The sub gigahertz radio communication through the serial peripheral interface can be secured, preventing interaction from non-secure sources. It provides a differential-receive input and a separate single-ended transmit output for high power to plus 22 dBm and default power up to max plus 14 dBm. The sub gigahertz radio can operate independently from the CPU. This means the CPU system can be in one of its low power modes while the radio is receiving or transmitting data. The sub gigahertz radio module is accessed through the sub gigahertz serial peripheral interface using SPI commands. It consists of a controller part containing the data handling and control logic, a lower modem and a frequency shift keying and minimum shift keying modem, and the radio front end, containing the transmit chain with the power amplifier regulator, the received chain, the high-speed external 32 MHz oscillator, and the temperature-controlled crystal oscillator regulator. Current interrupts are provided to the CPU, as well as sub gigahertz radio busy information. The high-speed external 32 MHz clock control enables the control of the high-speed external 32 MHz oscillator and its operation mode, including the temperature-controlled crystal oscillator regulator operation. The lower modem has two framing configurations, explicit packet mode using more overhead leading to increased airtime. This packet type allows transfer of packets with variable-length payloads due to the inclusion of a header field, and implicit packet mode with minimum overhead leading to minimum airtime. This packet type requires the transfer of all packets with a predefined fixed-length payload. It does not include a header field. The preamble length can be configured. The modem can be configured to trade off effective data rate versus range with the programmable modulation bandwidth and or spreading factor. A lower modulation bandwidth and or spreading factor allows the increase of the range. The coding rate also improves the robustness against interferences at the expense of longer packet airtime. The higher the coding rate, the more robust the communication will be. The preamble activity detection can be used to detect the presence of a laura signal before initiating any communication. The generic framing is used with frequency shift keying and minimum shift keying modulation and uses a non-return to zero coding. The preamble length can be configured. An optional access address field can be added for which the length can be configured. The preamble length packet mode using more overhead leading to increased airtime. This packet time allows the transfer of packets with variable length payloads due to the inclusion of a header field. Fixed length packet mode with minimum overhead leading to minimum airtime. This packet type requires the transfer of all packets with a predefined fixed-length payload. It does not include a header field. Currently whitening can be added to the payload. The cyclic redundancy check is fully programmable for polynomial, initialization value, CRC inversion and length. The frequency shift keying modem can be configured for the following configurations. Bit rate, Gaussian filtering, modulation bandwidth, and frequency deviation. The minimum shift keying modem is only available in transmit mode and can be configured for the following configurations, bit rate and Gaussian filtering. The binary phase shift keying modem is only available in transmit mode. The binary phase shift keying framing is fully flexible and fully under firmware control. Any preamble, access address, header field, payload and CRC shall be provided by firmware. The binary phase shift keying modem can only be configured for bit rate. With some data preprocessing, differential binary phase shift keying modulation can be obtained. The sub gigahertz radio operating modes are depicted in this figure. In the startup phase, some internal sub gigahertz radio supply and clock startup, after which the sleep state is entered. The sleep state represents the lowest power mode. There is no radio activity. Optionally, the sub gigahertz RTC timer can be kept running for duty-cycled operations. To exit the sleep state, firmware has to set the sub gigahertz serial peripheral interface NSS signal low. On a cold start, the calibration phase is used to calibrate some sub gigahertz radio blocks like the internal oscillator's frequency, radio phase-locked loop, radio analog to digital converter, and image rejection. Only once in standby state, the firmware can communicate with the sub gigahertz radio through the sub gigahertz serial peripheral interface and program the configuration parameters before entering any active state. In the frequency synthesis state, the radio PLL locks on the requested radio frequency. Then transmit and receive states can be entered. In the transmit and receive states, actual data is transferred on the radio frequency with the selected modulation. Communication with the sub gigahertz radio is done through the command-based serial peripheral interface or SPI. The command structure uses a one-byte opcode to identify the command followed by the command parameters. The number of parameters depends on the command. A busy information is provided that indicates when the sub gigahertz radio can't receive commands, such as when the current requested command is being processed or when a low power mode is entered. Data for transmit and receive is in the sub gigahertz radio 256-byte data buffer RAM. The transmit and receive data buffers are accessed via the sub gigahertz radio serial peripheral interface command. The RAM has a circular nature. Any address increment exceeding 0xFF wraps around to address 0x00. The transmit buffer is written by firmware and read by hardware. The start of the transmit buffer is defined by the transmit base address. The length of the buffer is defined by the payload length. The hardware uses the transmit buffer pointer to read the data. The receive buffer is written by hardware and read by firmware. The start of the receive buffer is defined by the receive base address. The hardware uses the receive start buffer pointer to start reading the data. Data is read until the length of the buffer as defined by the receive payload length. Note that if the amount of received data exceeds the received buffer length, other data in the RAM are overwritten. This slide lists the subsequent steps to perform a basic Lora transmission. This slide lists the subsequent steps to perform a basic Lora reception. This slide lists the subsequent steps to perform a basic transmission using binary phase shift keying or BPSK modulation.