MC68HC08AS32 Datasheet, PDF (359/394 Pages) Motorola, Inc – M68HC08 Family of 8-bit microcontroller units (MCUs)

Byte Data Link Controller-Digital (BDLC-D)
BDLC CPU Interface
TEOD — Transmit End of Data Bit
This bit is set by the programmer to indicate the end of a message is
being sent by the BDLC. It will append an 8-bit CRC after completing
transmission of the current byte. This bit also is used to end an
in-frame response (IFR). If the transmit shadow register is full when
TEOD is set, the CRC byte will be transmitted after the current byte in
the Tx shift register and the byte in the Tx shadow register have been
transmitted. (See 20.6.3 Rx and Tx Shadow Registers for a
description of the transmit shadow register.) Once TEOD is set, the
transmit data register empty flag (TDRE) in the BDLC state vector
register (BSVR) is cleared to allow lower priority interrupts to occur.
(See 20.7.4 BDLC State Vector Register.)
1 = Transmit end-of-data (EOD) symbol
0 = The TEOD bit will be cleared automatically at the rising edge of
the first CRC bit that is sent or if an error is detected. When
TEOD is used to end an IFR transmission, TEOD is cleared
when the BDLC receives back a valid EOD symbol or an error
condition occurs.
TSIFR, TMIFR1, and TMIFR0 — Transmit In-Frame Response
Control Bits
These three bits control the type of in-frame response being sent. The
programmer should not set more than one of these control bits to a 1
at any given time. However, if more than one of these three control
bits are set to 1, the priority encoding logic will force these register bits
to a known value as shown in Table 20-5. For example, if 011 is
written to TSIFR, TMIFR1, and TMIFR0, then internally they will be
encoded as 010. However, when these bits are read back, they will
read 011.
Table 20-5. BDLC Transmit In-Frame Response
Control Bit Priority Encoding
Write/Read
TSIFR
0
1
0
0
Write/Read
TMIFR1
0
X
1
0
Write/Read
TMIFR0
0
X
X
1
Actual
TSIFR
0
1
0
0
Actual
TMIFR1
0
0
1
0
Actual
TMIFR0
0
0
0
1
MC68HC08AS32 — Rev. 3.0
MOTOROLA
Byte Data Link Controller-Digital (BDLC-D)
Advance Information
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