Notes On Using Lin-Uart - Fujitsu MB95630H Series Hardware Manual

CHAPTER 14 LIN-UART

14.8 Notes on Using LIN-UART

14.8 Notes on Using LIN-UART
This section provides notes on using the LIN-UART.
■ Notes on Using LIN-UART
● Enabling operation
The LIN-UART has the TXE bit and the RXE bit in the LIN-UART serial control register
(SCR) to enable transmission and reception respectively. Since both transmission and reception
are disabled by default (initial values), they must be enabled before the transfer starts.
Transmission and reception can be disabled to stop transfer if necessary.
● Setting communication mode
The communication mode should be set while the LIN-UART stops operating. If the
communication mode is set while transmission or reception is in progress, the integrity of data
being transmitted or received at the setting of the mode is not guaranteed.
● Timing of enabling transmit interrupts
Since the default (initial) value of the transmit data register empty flag bit (SSR:TDRE) is "1"
(no transmit data, transmit data write enabled), a transmit interrupt request is made
immediately after the transmit interrupt request is enabled (SSR:TIE = 1). To prevent any
transmit interrupt request from being made, always set the TIE flag bit to "1" after setting
transmit data.
● Modifying operation settings
With the sampling clock edge select bit (ESCR:SCES) set to "0", before modifying any of the
bits listed below, disable reception and transmission. After modifying them, reset the LIN-
UART with a software reset.
• Serial control register (SCR)
Parity enable bit (PEN), stop bit length select bit (SBL), data length select bit (CL)
• Serial mode register (SMR)
Operating mode select bits (MD[1:0])
• Extended status control register (ESCR)
Continuous clock output enable bit (CCO)
• Extended communication control register (ECCR)
Serial clock transmission/reception side select bit (MS), serial clock delay enable bit
(SCDE), start/stop bits mode enable bit (SSM)
To reset the LIN-UART with a software reset (SMR:UPCL = 1), finish modifying the settings
of the SMR register first, and then access the register again.
In the case of not following the above procedure to modify operating settings, proper
operations of this device cannot be guaranteed.
Though the transmission bit length of the LIN break field is variable, the detection bit length of
the LIN break field is fixed at 11 bits.
258 FUJITSU SEMICONDUCTOR LIMITED
MB95630H Series
MN702-00009-1v0-E