Rainbow-electronics ATmega64M1 Manuel d'utilisateur télécharger pdf (Page 197)

197

8209A–AVR–08/09

ATmega16M1/32M1/64M1

• Bit 2 – RTRMSK: Remote Transmission Request Mask

– 0 - comparison true forced

– 1 - bit comparison enabled.

• Bit 1 – Reserved Bit

Writing zero in this bit is recommended.

• Bit 0 – IDEMSK: Identifier Extension Mask

– 0 - comparison true forced

– 1 - bit comparison enabled.

20.11.5 CANSTML and CANSTMH – CAN Time Stamp Registers

• Bits 15:0 - TIMSTM[15:0]: Time Stamp Count

CAN time stamp counter range 0 to 65,535.

20.11.6 CANMSG – CAN Data Message Register

• Bit 7:0 – MSG[7:0]: Message Data

This register contains the CAN data byte pointed at the page MOb register.

After writing in the page MOb register, this byte is equal to the specified message location of the

pre-defined identifier + index. If auto-incrementation is used, at the end of the data register writ-

ing or reading cycle, the index is auto-incremented.

The range of the counting is 8 with no end of loop (0, 1,..., 7, 0,...).

20.12 Examples of CAN Baud Rate Setting

The CAN bus requires very accurate timing especially for high baud rates. It is recommended to

use only an external crystal for CAN operations.

(Refer to “Bit Timing” on page 171 and “Baud Rate” on page 173 for timing description and page

188 to page 190 for “CAN Bit Timing Registers”).

Bit 76543210

TIMSTM7 TIMSTM6 TIMSTM5 TIMSTM4 TIMSTM3 TIMSTM2 TIMSTM1 TIMSTM0 CANSTML

TIMSTM15 TIMSTM14 TIMSTM13 TIMSTM12 TIMSTM11 TIMSTM10 TIMSTM9 TIMSTM8 CANSTMH

Bit 151413121110 9 8

Read/WriteRRRRRRRR

Initial Value - - - - - - - -

Bit 76543210

MSG 7 MSG 6 MSG 5 MSG 4 MSG 3 MSG 2 MSG 1 MSG 0 CANMSG

Read/Write R/W R/W R/W R/W R/W R/W R/W R/W

Initial Value--------

1 2 ... 192 193 194 195 196 197 198 199 200 201 202 ... 342 343

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Rainbow-electronics ATmega64M1 Manuel d'utilisateur Page 197