The X-NUCLEO-IDS01A4 is an evaluation board based on the SPIRIT1 RF module SPSGRF-868 expansion of STM32 Nucleo boards.
The SPSGRF-868 module operates in the 868 MHz ISM band and is ETSI certified. Identification of the operating frequency of the X-NUCLEO-IDS01Ax (x=4 or 5) is performed through two resistors (R14 and R15).
It is compatible with the MORPHO and Arduino UNO R3 connector layout. The X-NUCLEO-IDS01A4 interfaces with the STM32 microcontroller via SPI connections and GPIO pins. The user can change some of the GPIOs by mounting or removing the resistors.
Key Features
STM32 Nucleo expansion board based on the SPSGRF-868
SPGRF-868 characteristics:
868 MHz ETSI-certified module based on low power, low data-rate sub-1 GHz SPIRIT1 transceiver
Integrated Balun (BALF-SPI-01D3)
Chip antenna
Compatible with STM32 Nucleo boards
Equipped with Arduino UNO R3 connectors
Scalable solution; capable of cascading multiple boards for larger systems
Example firmware for point-to-point communication, compatible with STM32Cube firmware
raw os 采用了特殊的机制, 可以降低整个系统的最大关中断时间无限接近0us.其主要实现原理是原先系统关中断的地方改为关抢占,这样就可以把系统最大中断时间降为最低了。读者可以看到RAW_CRITICAL_ENTER()的实现有两种实现方式,第一种是传统的关中断形式:#defineRAW_CRITICAL_ENTER()RAW_CPU_DISABLE()第二种是关抢占形式:#defineRAW_