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FlexRay Communication Controller (FlexRAY)
PXN20 Microcontroller Reference Manual, Rev. 1
26-104
Freescale Semiconductor
, the application shall write to the message buffer data field and change the
commit bit CMT only if the transmit message buffer is in one of the states HDis, HDisLck, HLck,
HLckCCSa, HLckCCMa, or HLckCCMa. The application can change the state of a message buffer if it
issues the appropriate commands shown in
. The state change is indicated through the
MBCCSR
n
[EDS] and MBCCSR
n
[LCKS] status bits.
If the transmit message buffer enters one of the states HDis, HDisLck, HLck, HLckCCSa, HLckCCMa, or
HLckCCMa the MBCCSR
n
[DVAL] flag is negated.
26.6.6.2.5
Message Transmission
As a result of the message buffer search described in
Section 26.6.7, Individual Message Buffer Search,
the controller triggers the message available transition MA for as many as two transmit message buffers.
This changes the message buffer state from Idle to CCMa and the message buffers can be used for message
transmission in the next slot.
The controller transmits a message from a message buffer if both of the following two conditions are
fulfilled at the start of the transmission slot:
1. the message buffer is in the message available state CCMa
2. the message data are still valid (MBCCSR
n
[CMT] = 1)
In this case, the controller triggers the TX transition and changes the message buffer state to CCTx. A
transmit message buffer timing and state change diagram for message transmission is given in
. In this example, the message buffer with message buffer number
n
is Idle at the start of the
search slot, matches the slot and cycle number of the next slot, and message buffer data are valid
(MBCCSR
n
[CMT] = 1).
Figure 26-121. Message Transmission Timing
Figure 26-122. Message Transmission from HLck state with unlock
search[s+1]
MT s
tar
t
MA
slot s
TX
SU
CCMa
CCTx
slot s+1
Idle
MT s
tar
t
Idle
slot s+2
slo
t s
tart
slo
t s
tart
slo
t s
tart
MT s
tar
t
message transmit
SSS
CCSu
search[s+1]
MT st
art
MT s
tar
t
MA
slot s
TX
SSS
HLckCCMa CCTx
slot s+1
HLck
MT s
tar
t
Idle
slot s+2
sl
ot start
slot start
slot start
HU
CCMa
message transmit
Summary of Contents for PXN2020
Page 1: ...PXN20 Microcontroller Reference Manual Devices Supported PXN2020 PXN2120 PXN20RM Rev 1 06 2011...
Page 42: ...PXN20 Microcontroller Reference Manual Rev 1 lxiv Freescale Semiconductor...
Page 64: ...Introduction PXN20 Microcontroller Reference Manual Rev 1 1 22 Freescale Semiconductor...
Page 112: ...Signal Description PXN20 Microcontroller Reference Manual Rev 1 3 44 Freescale Semiconductor...
Page 118: ...Resets PXN20 Microcontroller Reference Manual Rev 1 4 6 Freescale Semiconductor...
Page 372: ...e200z6 Core Z6 PXN20 Microcontroller Reference Manual Rev 1 13 8 Freescale Semiconductor...
Page 412: ...e200z0 Core Z0 PXN20 Microcontroller Reference Manual Rev 1 14 14 Freescale Semiconductor...
Page 821: ...Media Local Bus MLB PXN20 Microcontroller Reference Manual Rev 1 Freescale Semiconductor 27 49...
Page 822: ...Media Local Bus MLB PXN20 Microcontroller Reference Manual Rev 1 27 50 Freescale Semiconductor...
Page 1376: ...Memory Map PXN20 Microcontroller Reference Manual Rev 1 A 118 Freescale Semiconductor...