ADSP-BF537 Blackfin Processor Hardware Reference
9-21
CAN Module
If the mailbox is configured for automatic remote frame handling, the
time stamp value is written for transmission of a data frame (mailbox con-
figured as transmit) or the reception of the requested data frame (mailbox
configured as receive).
The counter can be cleared (set
UCRC
bit to 1) or disabled (set
UCE
bit to 0)
by writing to the
CAN_UCCNF
register. The counter can also be loaded with
a value by writing to the counter register itself (
CAN_UCCNT
).
It is also possible to clear the counter (
CAN_UCCNT
) by reception of a mes-
sage in mailbox number 4 (synchronization of all time stamp counters in
the system). This is accomplished by setting the
UCCT
bit in the
CAN_UCCNF
register.
An overflow of the counter sets a bit in the global interrupt status register
(
UCEIS
in the
CAN_GIS
register). A global interrupt can optionally occur by
unmasking the bit in the global interrupt mask register (
UCEIM
in the
CAN_GIM
register). If the interrupt source is unmasked, a bit in the global
interrupt flag register is also set (
UCEIF
in the
CAN_GIF
register).
Temporarily Disabling Mailboxes
If a mailbox is enabled and configured as “transmit,” write accesses to the
data field are denied. If this mailbox is used for automatic remote frame
handling, the data field must be updated without losing an incoming
remote request frame and without sending inconsistent data. Therefore,
the CAN controller allows for temporary mailbox disabling, which can be
enabled by programming the mailbox temporary disable register
(
CAN_MBTD
).
The pointer to the requested mailbox must be written to the
TDPTR[4:0]
bits of the
CAN_MBTD
register and the mailbox temporary disable request bit
(
TDR
) must be set. The corresponding mailbox temporary disable flag (
TDA
)
is subsequently set by the internal logic.
Summary of Contents for Blackfin ADSP-BF537
Page 42: ...Contents xlii ADSP BF537 Blackfin Processor Hardware Reference ...
Page 90: ...Development Tools 1 32 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 138: ...Programming Examples 4 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 340: ...SDC Programming Examples 6 84 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 606: ...Programming Examples 9 94 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 660: ...Programming Examples 10 54 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 720: ...Electrical Specifications 11 60 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 840: ...Programming Examples 13 42 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 876: ...Programming Examples 14 36 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 938: ...Programming Examples 15 62 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 958: ...Programming Examples 17 12 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 986: ...Programming Examples 18 28 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 1162: ...G 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 1218: ...Index I 56 ADSP BF537 Blackfin Processor Hardware Reference ...