SNIP_CLASSIC_CANTRCV_SECTION_7_7_Preconditions_for_driver_initialization

7.7 Preconditions for driver initialization [SWS_CanTrcv_00099] Upstream requirements: SRS_BSW_00172 ⌈The environment of the CanTrcv module shall make sure that all necessary BSW drivers (used by the CanTrcv module) have been initialized and are usable before CanTrcv_Init is called.⌋ The CAN bus transceiver driver uses drivers for Spi and Dio to control the CAN bus transceiver hardware. Thus, these drivers must be available and ready to operate before the CAN bus transceiver driver is initialized. The CAN transceiver driver may have timing requirements for the initialization sequence and the access to the transceiver device which must be fulfilled by these used underlying drivers. The timing requirements might be that 1. The call of the CAN bus transceiver driver initialization has to be performed very early after power up to be able to read all necessary information out of the transceiver hardware in time for all other users within the ECU. 2. The runtime of the used underlying services is very short and synchronous to enable the driver to keep his own timing requirements limited by the used hardware device. 3. The runtime of the driver may be enlarged due to some hardware devices configuring the port pin level to be valid for e.g. 50µs before changing it again to reach a specific state (e.g. sleep).