- 您现在的位置：买卖IC网 > PDF目录98013 > MCP25020-I/P SPECIALTY MICROPROCESSOR CIRCUIT, PDIP14 PDF资料下载
参数资料
| 型号： | MCP25020-I/P |
| 元件分类： | 微控制器/微处理器 |
| 英文描述： | SPECIALTY MICROPROCESSOR CIRCUIT, PDIP14 |
| 封装： | 0.300 INCH, PLASTIC, DIP-14 |
| 文件页数： | 3/66页 |
| 文件大小： | 1028K |
| 代理商： | MCP25020-I/P |
第1页第2页当前第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页第29页第30页第31页第32页第33页第34页第35页第36页第37页第38页第39页第40页第41页第42页第43页第44页第45页第46页第47页第48页第49页第50页第51页第52页第53页第54页第55页第56页第57页第58页第59页第60页第61页第62页第63页第64页第65页第66页
2007 Microchip Technology Inc.
DS21664D-page 11
MCP2502X/5X
2.5
Buffers, Masks, and Filters
This part of the CAN module supports the transmitting,
receiving and acceptance of CAN messages.
Three transmit buffers are used for the three transmit
message IDs, as discussed later in this section. Two
receive buffers store the CAN message’s arbitration
field, control field and the data field.
One mask defines which bits are to be applied to either
filter. The mask can be regarded as defining “don’t
care” bits for the filter.
Each of the two filters define a bit pattern that will be
compared to all incoming messages. All filter bits that
have not been defined as “don’t care” by the mask are
applied to the message.
2.5.1
TRANSMIT MESSAGE ID’S
The MCP2502X/5X device contains three separate
transmit message ID’s: TXID0, TXID1 and TXID2. The
data length code is predefined for each of the various
output messages, with the data that is transmitted
coming directly from the contents of the device’s
peripheral registers.
2.5.1.1
Transmit Message ID0 (TXID0)
TXID0 contains the identifier that is used when trans-
mitting
the
On
Bus
message.
If
enabled
(STCON.STEN = 1), the On Bus message will be
transmitted at predefined intervals. Depending on the
message-select bit (STCON.STMS = 1), the CAN
message will send GPIO and A/D data.
Transmit Message ID0 will not automatically be sent
when the device is brought out of sleep.
2.5.1.2
Transmit Message ID1 (TXID1)
TXID1 contains the identifier that is used when the
MCP2502X/5X sends the Command Acknowledge
message, the Receive Overflow message and/or the
Error Condition message. All message types use the
same identifier.
The CAEN bit, in the OPTREG2 register, selects
between the Command Acknowledge and Receive
Overflow operation. These message types have a DLC
of 0 and do not contain any data. The Error Condition
message can occur anytime, has a DLC of 3 and
contains the EFLG, TEC and REC data values.
Command Acknowledge: TXID1 sends a Command
Acknowledge message when the MCP2502X/5X
receives an Input Message and processes the
instruction (and OPTREG2.CAEN = 1). This message
is used as a hand shake for the node requesting the
modification of the MCP2502X/5X. There is no data
associated with this message.
Receive Overflow: TXID1 sends a Receive Overflow
message if there is a Receive Overflow condition (and
OPTREG2.CAEN = 0). This only occurs if the device
has received a valid message before processing the
previous valid message from the same receive buffer.
There is no data associated with this message.
Error Condition: An Error Condition message is
transmitted if the TEC or REC counters reach error
warning (> 95) or error passive (> 127). This message
contains the TXID1 identifier and the TEC, REC and
EFLG counters.
A hysteresis is implemented in hardware that prevents
messages from repeatedly being transmitted due to
error counts changing by one or two bits. Once a
message is sent for an error warning (TEC or REC >
95), the message will not trigger again until the error
counter
≤ 79 and back to > 95 (hysteresis = 17 counts).
Similarly, an error passive message is sent at TEC or
REC > 127 and is not sent again until the error counter
≤ 111 and back to >127 (hysteresis = 17 counts).
2.5.1.3
Transmit Message ID2 (TXID2)
Transmit ID2 contains the identifier that is used when
transmitting
auto-conversion-initiated
messages,
including digital input edge detection and/or analog
input exceeding a threshold. This message will also be
sent when the device wakes up from sleep due to a
digital input change-of-state condition (i.e., change-of-
state occurs on input configured to transmit on
change-of-state).
2.6
Receive Buffers
The MCP2505X contains two receive buffers, each
with their own filter. There is also a Message Assembly
Buffer (MAB) that acts as a third receive buffer (see
The two receive buffers, combined with the MAB help,
insure that received messages will be processed while
minimizing the chances of receive buffer overrun due to
maximum bus loading of messages destined for the
MCP2502X/5X.
Note:
A zero data length On Bus message will be
transmitted
once
after
power-up,
regardless of scheduled transmission-
enable status.
Note:
The receive buffers are used by the
MCP2502X/5X to implement the command
messages
and
are
not
externally
accessible.
相关PDF资料 |
PDF描述 |
|---|---|
| MCP25050T-E/SL | SPECIALTY MICROPROCESSOR CIRCUIT, PDSO14 |
| MCP25055-I/SL | SPECIALTY MICROPROCESSOR CIRCUIT, PDSO14 |
| MCP2510T-E/P | 2 CHANNEL(S), 1M bps, LOCAL AREA NETWORK CONTROLLER, PDIP18 |
| MCZ33781EK | SPECIALTY MICROPROCESSOR CIRCUIT, PDSO32 |
| MD1802FH | 10 A, 700 V, NPN, Si, POWER TRANSISTOR, TO-220AB |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MCP25020T | 制造商:MICROCHIP 制造商全称:Microchip Technology 功能描述:CAN I/O Expander Family |
| MCP25020TE/P | 制造商:MICROCHIP 制造商全称:Microchip Technology 功能描述:CAN I/O Expander Family |
| MCP25020TE/SL | 制造商:MICROCHIP 制造商全称:Microchip Technology 功能描述:CAN I/O Expander Family |
| MCP25020T-E/SL | 功能描述:网络控制器与处理器 IC Digital CAN I/O RoHS:否 制造商:Micrel 产品:Controller Area Network (CAN) 收发器数量: 数据速率: 电源电流（最大值）:595 mA 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:PBGA-400 封装:Tray |
| MCP25020TI/P | 制造商:MICROCHIP 制造商全称:Microchip Technology 功能描述:CAN I/O Expander Family |
发布紧急采购，3分钟左右您将得到回复。