Datasheet

MC9S08EL32 Series and MC9S08SL16 Series Data Sheet, Rev. 3
202 Freescale Semiconductor
12.3.6 SLIC Data Length Code Register (SLCDLC)
The SLIC data length code register (SLCDLC) is the primary functional control register for the SLIC
module during normal LIN operations. It contains the data length code of the message buffer, indicating
how many bytes of data are to be sent or received, as well as the checksum mode control and transmit
enabling bit.
76543210
R
TXGO CHKMOD DLC5 DLC4 DLC3 DLC2 DLC1 DLC0
W
Reset00000000
Figure 12-10. SLIC Data Length Code Register (SLCDLC)
Table 12-10. SLCDLC Field Descriptions
Field Description
7
TXGO
SLIC Transmit Go — This bit controls whether the SLIC module is sending or receiving data bytes. This bit is
automatically reset to 0 after a transmit operation is complete or an error is encountered and transmission has
been aborted.
0 SLIC receive data
1 Initiate SLIC transmit— The SLIC assumes the user has loaded the proper data into the message buffer and
will begin transmitting the number of bytes indicated in the SLCDLC bits. If the number of bytes is greater than
8, the first 8 bytes will be transmitted and an interrupt will be triggered (if unmasked) for the user to enter the
next bytes of the message. If the number of bytes is 8 or fewer, the SLIC will transmit the appropriate number
of bytes and automatically append the checksum to the transmission. If IMSG or TXABRT are set or the SLCF
flag is set, writes to TXGO will have no effect.
6
CHKMOD
LIN Checksum Mode — CHKMOD is used to decide what checksum method to use for this message frame.
Resets after error code or message frame complete. CHKMOD must be written (124 desired) only after the
reception of an identifier and before the reception or transmission of data bytes. Writing this bit to a one clears
the current checksum calculation.
0 Checksum calculated 119 the identifier byte included
(SAE J2602/LIN 2.0)
1 Checksum calculated without the identifier byte (LIN spec <= 1.3)
5:0
DLC
Data Length Control Bits — The value of the bits indicate the number of data bytes in message. Values
0x00–0x07 are for “normal” LIN messaging. Values 0x08–0x3F are for “extended” LIN messaging. See
Ta bl e 1 2-1 1.
Table 12-11. Data Length Control
DLC[5:0] Message Data Length (Number of Bytes)
0x00 1
0x01 2
0x02 3
... ...
0x3D 62
0x3E 63
0x3F 64