MC68HC908QL4 Datasheet, PDF (159/226 Pages) Motorola, Inc – Microcontrollers

Initialization/Application Information
(CHKMOD), as well as signal the SLIC that the buffer is ready by writing a 1 to TXGO. TXGO will remain
set to 1 until the buffer is sent successfully or an error is encountered, signaling to the application code
that the buffer is in process of transmitting. In cases of 1–8 data bytes only being sent (standard LIN
request frames), the SLIC automatically calculates and transmits the checksum byte at the end of the
message frame. The user can exit the ISR after SLCDLC has been written and the SLCF flag has been
cleared.
PROCESS
REQUEST MESSAGE
EXTENDED FRAME ^Y
?
N
1. CLEAR SLCF
2. LOAD DATA INTO MESSAGE BUFFER
3. WRITE SLCDLC FOR THIS ID
1n00 0xxx
(TXGO = 1)
(CHKMOD = n)
1. CLEAR SLCF
2. INITIALIZE SW BYTE COUNT
3. LOAD FIRST 8 DATA BYTES
4. WRITE SLCDLC FOR THIS ID
1nxx xxxx
(TXGO = 1)
(CHKMOD = n)
EXIT ISR
EXIT ISR
PROCESS ERROR CODE:
BYTE FRAMING ERROR
BIT-ERROR
CHECKSUM-ERROR
EXIT ISR
RETURN TO IDLE
INTERRUPT
READ SLCSV
CLEAR SLCF
Y
ERROR CODE
?
N
TRANSMIT COMPLETE
INTERRUPT
READ SLCSV
CLEAR SLCF
ERROR CODE
Y
?
N
DECREMENT SW BYTE COUNT BY 8
PROCESS ERROR CODE:
BYTE FRAMING ERROR
BIT-ERROR
EXIT ISR
RETURN TO IDLE
LAST FRAME ^N
(SW BYTE COUNT £8)
?
Y
1. LOAD LAST (£8) BYTES TO TRANSMIT
2. WRITE TXGO BIT TO START TRANSMIT⁽¹⁾
1. LOAD NEXT 8 BYTES TO TRANSMIT
2. WRITE TXGO BIT TO START TRANSMIT⁽¹⁾
Note 1. When writing TXGO bit only, ensure that CHKMOD and data length values are not accidentally modified.
Figure 14-17. Handling Request LIN Message Frames
MC68HC908QL4 Data Sheet, Rev. 7
Freescale Semiconductor
159