Filter
Top Products
238
CHAPTER 14 16-BIT RELOAD TIMER
14.1 Overview of the 16-bit Reload Timer
The 16-bit reload timer has the following functions:
• The count clock can be selected from three internal clocks and external event clocks.
• A software trigger or external trigger can be selected as the start trigger.
• If the 16-bit timer register (TMR) underflows, an interrupt can be generated to the
CPU. The 16-bit reload timer can be used as an interval timer by using an interrupt.
• If the TMR underflows, either the one-shot mode for stopping the TMR count
operation, or the reload mode for reloading the value of the 16-bit reload register
(TMRLR) to the TMR to continue the TMR count operation can be selected.
• The 16-bit reload timer corresponds to the EI
2
OS (correspond to 2 channels).
• The MB90360 series has two channels of 16-bit reload timers.
■ Operation Modes of 16-bit Reload Timer
Table 14.1-1 indicates the operation modes of the 16-bit reload timer.
■ Internal Clock Mode
• When the count clock select bits in the timer control status register (TMCSR:CSL1, CSL0) are set to
"00
B
", "01
B
" or "10
B
", the 16-bit reload timer is set in the internal clock mode.
• In the internal clock mode, the 16-bit reload timer decrements in synchronization with the internal clock.
• The count clock select bits in the timer control status register (TMCSR:CSL1, CSL0) can be used to
select three count clock cycles.
• The start trigger sets the edge detection for a software trigger or an external trigger.
■ Event Count Mode
• When the count clock select bits in the timer control status register (TMCSR:CSL1, CSL0) are set to
"11
B
", the 16-bit reload timer is set to the event count mode.
• In the event count mode, the 16-bit reload timer decrements in synchronization with the edge detection
of the external event clock input to the TIN pin.
• A software trigger is selected as the start trigger.
• The 16-bit reload timer can be used as an interval timer by using a fixed cycle of the external clock.
Table 14.1-1 Operation Modes of 16-bit Reload Timer
Count clock Start trigger Operation performed upon underflow
Internal clock mode Software trigger
External trigger
One-shot mode
Reload mode
Event count mode Software trigger One-shot mode
Reload mode