mc68hc912d60c Freescale Semiconductor, Inc, mc68hc912d60c Datasheet - Page 329

• Manufacturer Part Number: mc68hc912d60c
• Description: Hc12 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

17.12.4 Data Segment Registers (DSRn)
17.12.5 Transmit Buffer Priority Registers (TBPR)
MC68HC912D60A — Rev. 3.1
Freescale Semiconductor
1. x is 5, 6, or 7 depending on which buffer Tx0, Tx1, or Tx2 respectively.
TBPR
$01xD
RESET
(1)
R
W
PRIO7
BIT 7
–
The eight data segment registers contain the data to be transmitted or
being received. The number of bytes to be transmitted or being received
is determined by the data length code in the corresponding DLR.
PRIO7 – PRIO0 — Local Priority
PRIO6
BIT 6
This field defines the local priority of the associated message buffer.
The local priority is used for the internal prioritisation process of the
msCAN12 and is defined to be highest for the smallest binary number.
The msCAN12 implements the following internal prioritisation
mechanism:
•
•
•
–
All transmission buffers with a cleared TXE flag participate in the
prioritisation immediately before the SOF (Start of Frame) is sent.
The transmission buffer with the lowest local priority field wins the
prioritisation.
In cases of more than one buffer having the same lowest priority,
the message buffer with the lower index number wins.
PRIO5
BIT 5
–
MSCAN Controller
PRIO4
BIT 4
–
PRIO3
BIT 3
–
Programmer’s Model of Message Storage
PRIO2
BIT 2
–
PRIO1
BIT 1
–
MSCAN Controller
Technical Data
PRIO0
BIT 0
–
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