AT90CAN128-16AE ATMEL Corporation, AT90CAN128-16AE Datasheet - Page 239

• Manufacturer Part Number: AT90CAN128-16AE
• Description: 8-bit Avr Microcontroller With 128K Bytes of Isp Flash And CAN Controller.flash (Kbytes) 128 Vcc (V) 2.7-5.5 EEPROM (Kbytes) 4 SRAM (bytes) 4K CAN (mess. Obj.) 15
• Manufacturer: ATMEL Corporation

Acceptance Filter
MOb Page
4250C–CAN–03/04
internal RxDcan
1. MObs in frame buffer receive mode need to be initialized as MObs in standard
2. The MObs are ready to receive data (or a remote) frames when their respective
3. When a frame identifier is received on CAN network, the CAN channel scans all the
4. On a hit, the IDT, the IDE and the DLC of the matched MOb are updated from the
5. Once the reception is completed, the data bytes of the received message are stored
6. When the reception in the last MOb of the set is completed, the frame buffer com-
7. All the parameters and data are available in the MObs until a new initialization.
Upon a reception hit (i.e., a good comparison between the ID + RTR + RBn + IDE
received and an IDT+ RTRTAG + RBnTAG + IDE specified while taking the comparison
mask into account) the IDT + RTRTAG + RBnTAG + IDE received are updated in the
MOb (written over the registers).
Figure 117. Acceptance Filter Block Diagram
Note:
Every MOb is mapped into a page to save place. The page number is the MOb number.
This page number is set in CANPAGE register. The number 15 is reserved for factory
tests.
CANHPMOB register gives the MOb having the highest priority in CANSIT registers. It is
formatted to provide a direct entry for CANPAGE register. Because CANHPMOB codes
CANSIT registers, it will be only updated if the corresponding enable bits (ENRX, ENTX,
ENERR) are enabled (c.f. Figure 121).
CANIDT Registers & CANCDMOB (MOb[i])
receive mode.
configurations are set (CONMOB).
MObs in receive mode, tries to find the MOb having the highest priority which is
matching.
incoming (frame) values.
(not for remote frame) in the data buffer of the matched MOb and the RXOK flag is
set (interrupt).
pleted BXOK flag is set (interrupt). BXOK flag can be cleared only if all CONMOB
fields of the set have been re-written before.
ID &RB
Examples:
To accept only ID = 0x317 in part A.
- ID MSK = 111 1111 1111 b
- ID TAG = 011 0001 0111 b
13(32)
Rx Shift Register (internal)
ID &RB
RTRTAG
Enable
Write
13(32)
13(32)
IDE
RTR
=
IDE
IDMSK
To accept ID from 0x310 up to 0x317 in part A.
- ID MSK = 111 1111 1000 b
- ID TAG = 011 0001 0xxx b
13(32)
1
CANIDM Registers (MOb[i])
13(32)
RTRMSK
AT90CAN128
IDEMSK
Hit MOb[i]
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