參數(shù)資料
型號： CR16MCS9VJE8
英文描述： Microcontroller
中文描述： 微控制器
文件頁數(shù)： 153/157頁
文件大小： 1256K
代理商： CR16MCS9VJE8
153
www.national.com
1. Message sent from another CAN node received into
buffer 1.
Buffer 1 and buffer 2 are tagged for reception of this
message.
2. Message sent from another CAN node received into
buffer 3 (ID=0x15555003).
Only buffer 3 is now tagged for reception.
3. CAN buffer 0 sends a frame (status set to TX_ONCE).
4. Status of CAN buffer 1 and 2 remains RX_READY, be-
cause they have not received the message sent by buff-
er 0.
26.1.3
CR16CAN Problem Solutions
Reset receive buffer tags before transmitting a message
The receive tag of a CAN receive buffer is reset when the
CPU updates the buffer status in the CNSTAT.ST-field to any
value which disables the receive buffer. Therefore the user
should write the sequence RX_NOT_ACTIVE - RX_READY
to all receive buffers which have an identifier filter matching
the identifier of the frame to be sent next before the message
is sent.
Modified CAN Communication Sequence:
(BUFFLOCK disabled)
The same CAN buffer settings as described in also apply to
this example.
1. Message sent from another CAN node received into
buffer 1.
Buffer 1 and buffer 2 are tagged for reception of this
message.
2. CPU reads out data from CAN buffer 1 and resets the
buffer state from RX_FULL to RX_READY.
3. Write RX_NOT_ACTIVE to CNSTAT.ST-field of buffer 1
and buffer 2.
Buffer 1 and buffer 2 are NOT tagged for reception any-
more.
4. Write RX_READY to CNSTAT.ST-field of buffer 1 and
buffer 2.
5. CAN buffer 0 sends a frame (status set to TX_ONCE).
6. Status of CAN buffer 1 remains RX_READY, because it
has NOT received the message sent by buffer 0.
Advantage:
No receive buffer is overwritten by a message sent by the
same CR16CAN node.
Disadvantage:
The corresponding receive buffers must be disabled for a
short period of time. During this time, when the receive buff-
ers are in the RX_NOT_ACTIVE state, correct incoming
messages from other CAN nodes will get lost.
This method is more suitable compared to the method de-
scribed in Section , if the number of transmit buffers with
identifier ID_RX_TX is lower than the number of receive buff-
ers set up with the corresponding identifier mask.
Reset receive buffer tags after reception of a message
The receive tag of a CAN receive buffer is reset when the
CPU updates the buffer status in the CNSTAT.ST-field to any
value which disables the receive buffer. Therefore the user
should write the sequence RX_NOT_ACTIVE - RX_READY
to this receive buffer, which has received the latest message.
Modified CAN Communication Sequence:
In the CAN communication example described below, the
buffer 14 is set up as basic CAN path, which is able to receive
all standard frames. The buffers 1 to 13 cannot receive the
frame sent by buffer 0.
Filter Masks:
BMSKB = 0xFFF0
BMSKX = 0x0000
Buffer configuration
:
1. Message sent from another CAN node received into
buffer 14.
Buffer 14 is tagged for reception of this message.
2. CPU reads out data from CAN buffer 14.
3. Write RX_NOT_ACTIVE to CNSTAT.ST-field of buffer
14.
Buffer 14 is NOT tagged for reception anymore.
4. Write RX_READY to CNSTAT.ST-field of buffer 14.
5. CAN buffer 0 sends a frame (status set to TX_ONCE).
6. Status of CAN buffer 14 remains RX_READY, because
it has NOT received the message sent by buffer 0.
Advantage:
No receive buffer is overwritten by a message sent by the
same CR16CAN node.
Disadvantage:
The corresponding receive buffers must be disabled for a
short period of time. During this time, when the receive buff-
ers are in the RX_NOT_ACTIVE state, correctly incoming
messages from other CAN nodes will get lost.
This method is more suitable compared to the method de-
scribed in Section , if the number of transmit buffers with
identifier ID_RX_TX is higher than the number of receive
buffers set up with the corresponding identifier mask. This is
the case if only the basic CAN path to buffer 14 is configured
to receive a range of identifiers, including the identifier
ID_RX_TX. All other buffers are configured with unique iden-
tifier filters.
Receive all frames and discard those, which were sent
by the same CR16CAN node.
Another approach to overcome this problem uses the Time
Stamp counter of the CR16CAN module to determine,
whether a message was sent and received at the same time.
This is the case when a transmitted frame is received by the
same CAN node.
CAN Buffer
Number
CAN Buffer Status
Buffer Identifier
0
TX_NOT_ACTIVE
any standard frame
14
RX_READY
ID1.IDE bit = 1
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參數(shù)描述
CR16MCS9VJE8/NOPB 功能描述:16位微控制器 - MCU RoHS:否 制造商:Texas Instruments 核心:RISC 處理器系列:MSP430FR572x 數(shù)據(jù)總線寬度:16 bit 最大時鐘頻率:24 MHz 程序存儲器大小:8 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:2 V to 3.6 V 工作溫度范圍:- 40 C to + 85 C 封裝 / 箱體:VQFN-40 安裝風(fēng)格:SMD/SMT
CR16MCS9VJE80 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Family of 16-bit CAN-enabled CompactRISC Microcontrollers
CR16MCS9VJE81 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Family of 16-bit CAN-enabled CompactRISC Microcontrollers
CR16MCS9VJE82 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Family of 16-bit CAN-enabled CompactRISC Microcontrollers
CR16MCS9VJE83 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Family of 16-bit CAN-enabled CompactRISC Microcontrollers
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