msm9225 Oki Semiconductor, msm9225 Datasheet - Page 8

• Manufacturer Part Number: msm9225
• Description: Can Controller Area Network Controller
• Manufacturer: Oki Semiconductor

¡ Semiconductor
FRM
(2) Transmission request: TRQ
(3) Receive status: RCS
(4) Receive completion interrupt enable: EIR
(5) Transmission completion interrupt enable: EIT
(6) Message format setting: FRM
(7) Automatic transmission : ARES
0
1
When a message is transmitted, the microcontroller writes "1" to this bit. When
transmission ends normally, CAN writes "0". This means that the TRQ bit is "1" during
transmission. Therefore, to request transmission, confirm that the TRQ bit is "0" first,
then write "1" to the TRQ bit. When the remote frame is received while the ARES bit is
"1", the TRQ bit is set to "1".
At reset, the TRQ bit is set to "0".
When receiving completes, the RCS bit becomes "1". Write "0" to the RCS bit before the
microcontroller calls up receive data. When receiving the remote frame, the RCS bit
becomes "1" just after the reception.
At reset, the RCS bit is set to "0".
The microcontroller sets interrupt request signal generation disable/enable when
receiving completes.
The EIR bit is valid when the EINTR bit of the CANI register is “1”.
At reset, the EIR bit is set to "0".
The microcontroller sets interrupt request signal generation disable/enable when
transmission completes.
The EIT bit is valid when the EINTT bit of the CANI register is “1”.
At reset, the EIT bit is set to "0".
The microcontroller sets the format of the message to be sent/received. A message in a
format other than the specified format cannot be sent/received.
For the relationship between setting and format, see the table below.
When a message specified to a group message is received, the content of the RTR bit is
written.
At reset, the FRM bit is set to "0".
If the data frame is automatically transmitted after remote frame reception, the ARES bit
should be set to "1".
At reset, the ARES bit is set to "0".
Standard message
Group message
Standard message
Group message
Message Type
Data frame
Transmission disable
Remote frame
Transmission disable
Transmission Format
Remote frame
Data frame
Data frame
Remote frame
Receive Format
MSM9225
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