Rainbow Electronics ATmega64C1 - Manual (Page 176)

176
7647A–AVR–02/08
ATmega32/64/M1/C1
5. Tsjw = (1 to 4) x Tscl = (SJW[1..0]+ 1) x Tscl
Notes: 1. The total number of Tscl (Time Quanta) in a bit time must be from 8 to 25.
2. PHS2[2..0] 2 is programmable to be
≤
PHS1[2..0] and
≥
1.
16.4.4 Fault Confinement
(c.f. Section 16.7 “Error Management” on page 181 ).
16.4.5 Overload Frame
An overload frame is sent by setting an overload request (OVRQ). After the next reception, the
CAN channel sends an overload frame in accordance with the CAN specification. A status or
flag is set (OVRF) as long as the overload frame is sent.
Figure 16-9. Overload Frame
16.5 Message Objects
The MOb is a CAN frame descriptor. It contains all information to handle a CAN frame. This
means that a MOb has been outlined to allow to describe a CAN message like an object. The set
of MObs is the front end part of the “mailbox” where the messages to send and/or to receive are
pre-defined as well as possible to decrease the work load of the software.
The MObs are independent but priority is given to the lower one in case of multi matching. The
operating modes are:
– Disabled mode
– Transmit mode
– Receive mode
– Automatic reply
– Frame buffer receive mode
16.5.1 Number of MObs
This device has 6 MObs, they are numbered from 0 up to 5 (i=5).
Ident "A" Cmd Message Data "A" CRC Interframe A Ident "B"
Overload Frame
Overload Frame RXCDAN
Setting OVRQ bit
OVFG bit
Resetting OVRQ bit
TXCDAN
OVRQ bit
Instructions