mc68hc912bd32 Freescale Semiconductor, Inc, mc68hc912bd32 Datasheet - Page 184

• Manufacturer Part Number: mc68hc912bd32
• Description: 16-bit Device Composed Of Standard On-chip Peripherals
• Manufacturer: Freescale Semiconductor, Inc

Transmit Process
Byteflight™ Module
MC68HC912BD32 Rev 1.0
A part or all of the message buffers can be configured as transmit
buffers. The set of transmit buffers must be contiguous in the register
map starting at buffer 15 and ending before the first receive buffer. A
message is submitted for transmission by unlocking the corresponding
non-empty (IFLG = 0) transmit buffer. The transmit buffer remains active
until the message is transmitted or aborted.
If there are several messages pending for transmission within the
interface, the message with the highest priority (lowest identifier) is
selected next. Only transmit buffers which were unlocked and full before
a sync pulse are transmitted in the following cycle. If there are two or
more transmit buffers with the same identifier, the buffer with the lowest
address wins the internal arbitration and will be transmitted, the
remaining buffer(s) with the same ID will be removed from the arbitration
process until the next communication cycle. A full buffer can be aborted
by setting the corresponding abort request bit. At the next sync pulse the
interrupt status flag (buffer is empty) and the abort acknowledge flag are
set if the buffer has been aborted. Only the interrupt status flag is set if
the buffer has been sent out.
1. All registers in reset state: Do not accept any valid system ID ($01...$FF).
2. Acceptance and rejection filter set to match same ID: Do not accept ID’s other than $55,
3. Accept all ID’s ($00 no valid system ID), then reject all ID’s with high nibble=0.
4. Do not accept ID’s $80 to $FF, accept all $00 to $7F ($00 no valid system ID), then reject
Stage I: Accept ID
Stage II: Reject ID
Freescale Semiconductor, Inc.
then reject $55.
all ID’s with bit 4 and 5 set.
Table 36 Acceptance/rejection filter mechanism - Examples
For More Information On This Product,
Receive ID
FIDRMR
FIDMR
FIDAR
FIDRJ
Go to: www.freescale.com
Byteflight™ Module
Example 1
none
$00
$00
$xx
$FF
$00
$00
(1)
Example 2
none
$55
$00
$55
$00
$55
$55
(2)
Example 3
$00...$FF
$00...$0F
$10...$FF
$xx
$FF
$0x
$0F
(3)
Example 4
%0xxx xxxx
%0111 1111
%xx11 xxxx
%1100 1111
$00...$7F
$30...$3F
$70...$7F
$00...$2F
$40...$6F
14-sibus
(4)