Command ID (16 bits)
31
msb
24
16
8
0
lsb
2
0 1
Optional parameter
Optional par.
extension
Pointer to command structure (bits 31:2)
31
msb
24
16
8
0
lsb
2
0 0
RF Core HAL
To get accurate synchronization, it is important that the system is running on the high-frequency crystal
oscillator starting before the CMD_SYNC_START_RAT command is run and extending to after the
CMD_SYNC_STOP_RAT command is finished.
For the CMD_SYNC_START_RAT and CMD_SYNC_STOP_RAT commands, that the AON_RTC:CTL
RTC_UPD_EN register bit must be set to 1 (see
,
AON_RTC:CTL Register
). It is never
necessary to reset this bit to 0; it may be set permanently to 1 when the RTC is started.
23.3 RF Core HAL
The RF core hides the complexity of the radio operations by providing a unified HAL to the system CPU.
23.3.1 Hardware Support
The radio HAL is supported by hardware, by means of the radio doorbell module in the RF core area and
command descriptors in the system RAM.
23.3.2 Firmware Support
The RF core accepts a set of high-level primitives. The following sections describe the desired
functionality at a high level.
23.3.2.1 Commands
The radio CPU lets the user run a set of high-level primitives or commands from the system CPU. After a
command has been issued through the CMDR register, the radio CPU examines it and decides a course
of action.
Three classes of commands are issued:
•
Radio operation command
•
Immediate command
•
Direct command
For the first two classes of commands, CMDR contains a pointer to a command structure. This pointer
must be a valid pointer with 32-bit word alignment, so the 2 least significant bits (LSBs) must be 0 0, as
shown in
. A direct command is signaled by setting the 2 LSBs to 01 and placing the command
ID number in bits 16 to 31 of CMDR. Bits 8 through 15, or alternatively 2 through 15, may be used as an
optional byte parameter.
shows the format for a direct command.
Figure 23-3. CMDR Register for Radio Operation Commands and Immediate Commands
Figure 23-4. CMDR Register for Direct Commands
The data structure pointed to by the CMDR register for radio operation and immediate commands may be
in the system RAM, the radio RAM, or flash (the latter is possible only if the radio CPU does not write
anything to the command structure). The system CPU must ensure that the memory area in use is free for
access, in particular when using the radio RAM, where a part of the memory is reserved for use by the
radio CPU. This information may be obtained with the CMD_GET_FW_INFO command (see
). The format of the command follows the structure given in
and its
subsection, and are defined in more detail specifically for each command.
1477
SWCU117C – February 2015 – Revised September 2015
Radio
Copyright © 2015, Texas Instruments Incorporated