Intel 87C196CB Manual De Usuario
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87C196CB SUPPLEMENT
7-4
7.3
CAN CONTROLLER OPERATION
This section describes the address map, message objects, message frames (which contain mes-
sage objects), error detection and management logic, and bit timing for CAN transmissions and
receptions.
sage objects), error detection and management logic, and bit timing for CAN transmissions and
receptions.
CAN_MSG
x
CON1
1E
y
1H
Message Object
x
Control 1
Program this register to indicate that a message is ready to
transmit or to initiate a transmission. Read this register to
determine whether the message object contains new data,
whether a message has been overwritten, whether software is
updating the message, and whether a transfer is pending.
transmit or to initiate a transmission. Read this register to
determine whether the message object contains new data,
whether a message has been overwritten, whether software is
updating the message, and whether a transfer is pending.
CAN_MSG
x
DATA0
CAN_MSG
x
DATA1
CAN_MSG
x
DATA2
CAN_MSG
x
DATA3
CAN_MSG
x
DATA4
CAN_MSG
x
DATA5
CAN_MSG
x
DATA6
CAN_MSG
x
DATA7
1E
y7
H
1E
y
8H
1E
y
9H
1E
y
AH
1E
y
BH
1E
y
CH
1E
y
DH
1E
y
EH
Message Object
x
Data 0–7
The data registers contain data to be transmitted or data received.
Do not use unused data bytes as scratch-pad memory; the CAN
controller writes random values to these registers during
operation.
controller writes random values to these registers during
operation.
CAN_MSG
x
ID0
CAN_MSG
x
ID1
CAN_MSG
x
ID2
CAN_MSG
x
ID3
1E
y
2H
1E
y
3H
1E
y
4H
1E
y
5H
Message Object
x
Identification 0–3
Write the message object’s ID to this register. (This register is the
same as the arbitration register of the 82527.)
same as the arbitration register of the 82527.)
CAN_MSK15
1E0CH, 1E0DH,
1E0EH, 1E0FH
Message 15 Mask
Program this register to mask (“don’t care”) specific message
identifier bits for message 15 in addition to those bits masked by a
global mask. The message 15 mask is ANDed with the standard
or extended global mask, so any “don’t care” bits defined in a
global mask are also “don’t care” bits for message 15.
identifier bits for message 15 in addition to those bits masked by a
global mask. The message 15 mask is ANDed with the standard
or extended global mask, so any “don’t care” bits defined in a
global mask are also “don’t care” bits for message 15.
CAN_SGMSK
1E06H, 1E07H
Standard Global Mask
Program this register to mask (“don’t care”) specific message
identifier bits for standard message objects.
identifier bits for standard message objects.
CAN_STAT
1E01H
Status
This register reflects the current status of the CAN controller.
INT_MASK1
0013H
Interrupt Mask 1
The CAN bit in this register enables and disables the CAN
interrupt request.
interrupt request.
INT_PEND1
0012H
Interrupt Pending 1
The CAN bit in this register, when set, indicates a pending CAN
interrupt request.
interrupt request.
Table 7-2. Control and Status Registers (Continued)
Register
Mnemonic
††
Register
Address
††
Description
†
The CCE bit in CAN_CON must be set to enable write access to the bit timing registers.
††
In register names,
x
= 1–15; in addresses,
y
= 1–F.