msm9225 Oki Semiconductor, msm9225 Datasheet - Page 6

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

Data Memory
¡ Semiconductor
FUNCTIONAL DESCRIPTION
A7
Before starting communication, messages for communication and various control registers
must be set at the data memory.
Addresses X0hex to XDhex are the message memory, which stores control registers, identifiers
and the contents of each message.
In this address space, the higher 4 bits of an address corresponds to the number of messages,
and a maximum of 16 (0Xhex to FXhex) can be stored. Each message has an area to store a
maximum of 8 bytes of data memory, 1 byte of control register, and a maximum of 5 bytes of
an identifier.
This means that the data memory capacity for messages is: 16 messages ¥ (8 bytes for a message
+ 1 byte for a control register + 5 bytes for an identifier) = 224 bytes.
Addresses XEhex to XFhex are allocated to the control registers.
The configuration of data memory is as follows
0
1
0
1
Corresponds to
number of
messages
A6
0
1
0
1
Ø
Ø
A5
0
1
0
1
Address
A4
0
1
0
1
A3
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
A2
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
Data memory configuration
A1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
A0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
IDFM = 0 (standard)
Message 0
Message 1
Message 2
Message 3
Message 4
Message 5
Message 6
Message 7
—
—
—
Message control register
Various control registers
Identifier 0
Identifier 1
Function
IDFM = 1 (extended)
Identifier 2
Identifier 3
Identifier 4
Message 0
Message 1
Message 2
Message 3
Message 4
Message 5
Message 6
Message 7
MSM9225
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