PXR40RM Datasheet, PDF (726/1434 Pages) Freescale Semiconductor, Inc – PXR40 Microcontroller

FlexRay Communication Controller (FLEXRAY)
22.6.18.2 Protocol Status Registers
The Protocol Status Register 2 (PSR2) provides slot status information about the Network Idle Time NIT
and the Symbol Window. The Protocol Status Register 3 (PSR3) provides aggregated slot status
information.
22.6.18.3 Slot Status Registers
The eight slot status registers, Slot Status Registers (SSR0–SSR7), can be used to observe the status of
static slots, dynamic slots, the symbol window, or the NIT without individual message buffers. These
registers provide all slot status related and received frame / symbol related status information, as given in
Table 22-116, except of the first valid indicator for non-transmission slots.
22.6.18.4 Slot Status Counter Registers
The controller provides four slot status error counter registers, Slot Status Counter Registers
(SSCR0–SSCR3). Each of these slot status counter registers is updated with the value of an internal slot
status counter at the start of a communication cycle. The internal slot status counter is incremented if its
increment condition, defined by the Slot Status Counter Condition Register (SSCCR), matches the status
vector provided by the PE. All static slots, the symbol window, and the NIT status are taken into account.
Dynamic slots are excluded. The internal slot status counting and update timing is shown in Figure 22-149.
incr. SSCRn_INT on error
SSCRn_INT not updated
incr. SSCRn_INT on error
SSCRn:= SSCRn_INT
SSCRn:= SSCRn_INT
slot 1
static segment
dynamic segment
symbol window
NIT
communication cycle
Figure 22-149. Slot Status Counting and SSCRn Update
The PE provides the status of the NIT in the first slot of the next cycle. Due to these facts, the SSCRn
register reflects, in cycle n, the status of the NIT of cycle n-2, and the status of all static slots and the
symbol window of cycle n-1.
The increment condition for each slot status counter consists of two parts, the frame related condition part
and the slot related condition part. The internal slot status counter SSCRn_INT is incremented if at least
one of the conditions is fulfilled:
1. frame related condition:
22-142
PXR40 Microcontroller Reference Manual, Rev. 1
Freescale Semiconductor