SWCU192 November 2021 CC1312R7 , CC1352P7 , CC2652P7 , CC2652R7
The system CPU is responsible for scheduling the commands as required. When using low-power modes, the system CPU must wake up a short time before the start of the next operation, using the RTC.
A radio operation command can be scheduled with a delayed start (see Section 26.3.2.5.1). If a command is started with a delay, the radio CPU goes to idle mode until the command starts. The radio operation command is considered to be running during this delay, and no other radio operation command can be scheduled unless the pending command is aborted or stopped first.
The system CPU can schedule back-to-back radio operation commands by using the next operation pointer in any radio operation command. This pointer can point to the next command to perform in the chain, and by this method, complex operations can be made. Under some conditions (such as an error or the expiration of a timer), the next command is not started. Instead, the operation ends or a number of commands may be skipped (see Section 26.3.2.5.2). If a new command is scheduled while another command is running, the system CPU must wait for the previous command or chain of commands to finish. The IEEE 802.15.4 commands have exceptions for this rule.
When a radio operation command is finished, the radio CPU raises a COMMAND_DONE interrupt to the system CPU. If a number of commands are chained as explained previously, the COMMAND_DONE interrupt is raised after each command, while the LAST_COMMAND_DONE interrupt is raised after the last command in the chain. For one nonchained command, the LAST_COMMAND_DONE interrupt is also raised after the command. When LAST_COMMAND_DONE is raised, COMMAND_DONE is always raised at the same time. Before raising the COMMAND_DONE interrupt, the radio CPU updates the status field of the command structure to a status that indicates the command is finished. The radio CPU does not access the command structure after raising the COMMAND_DONE interrupt.