Datasheet

RL78/L12 CHAPTER 6 TIMER ARRAY UNIT

R01UH0330EJ0200 Rev.2.00 176

Dec 13, 2013

6.1.3 8-bit timer operation function (channels 1 and 3 only)

The 8-bit timer operation function makes it possible to use a 16-bit timer channel in a configuration consisting of two 8-

bit timer channels. This function can only be used for channels 1 and 3.

Caution There are several rules for using 8-bit timer operation function.

For details, see 6.4.2 Basic rules of 8-bit timer operation function (channels 1 and 3 only).

6.1.4 LIN-bus supporting function (channel 5 only)

Timer array unit is used to check whether signals received in LIN-bus communication match the LIN-bus

communication format.

(1) Detection of wakeup signal

The timer starts counting at the falling edge of a signal input to the serial data input pin (RxD0) of UART0 and the

count value of the timer is captured at the rising edge. In this way, a low-level width can be measured. If the low-

level width is greater than a specific value, it is recognized as a wakeup signal.

(2) Detection of break field

The timer starts counting at the falling edge of a signal input to the serial data input pin (RxD0) of UART0 after a

wakeup signal is detected, and the count value of the timer is captured at the rising edge. In this way, a low-level

width is measured. If the low-level width is greater than a specific value, it is recognized as a break field.

(3) Measurement of pulse width of sync field

After a break field is detected, the low-level width and high-level width of the signal input to the serial data input pin

(RxD0) of UART0 are measured. From the bit interval of the sync field measured in this way, a baud rate is

calculated.

Remark For details about setting up the operations used to implement the LIN-bus, see 6.3.14 Input switch control