MC9RS08KA2 Datasheet, PDF (88/132 Pages) Freescale Semiconductor, Inc – Microcontrollers

Modulo Timer (RS08MTIMV1)
11.1.1 Features
Timer system features include:
• 8-bit up-counter
— Free-running or 8-bit modulo limit
— Software controllable interrupt on overflow
— Counter reset bit (TRST)
— Counter stop bit (TSTP)
• Four software selectable clock sources for input to prescaler:
— System bus clock — rising edge
— Fixed frequency clock (XCLK) — rising edge
— External clock source on the TCLK pin — rising edge
— External clock source on the TCLK pin — falling edge
• Nine selectable clock prescale values:
— Clock source divide by 1, 2, 4, 8, 16, 32, 64, 128, or 256
11.1.2 Modes of Operation
This section defines the MTIM’s operation in stop, wait and background debug modes.
11.1.2.1 Operation in Wait Mode
The MTIM continues to run in wait mode if enabled before executing the WAIT instruction. Therefore, the
MTIM can be used to bring the MCU out of wait mode if the timer overflow interrupt is enabled. For lowest
possible current consumption, the MTIM should be disabled by software if not needed as an interrupt
source during wait mode.
11.1.2.2 Operation in Stop Modes
The MTIM is disabled in all stop modes, regardless of the settings before executing the STOP instruction.
Therefore, the MTIM cannot be used as a wake up source from stop mode.
If stop is exited with a reset, the MTIM will be put into its reset state. If stop is exited with an interrupt,
the MTIM continues from the state it was in when stop was entered. If the counter was active upon entering
stop, the count will resume from the current value.
11.1.2.3 Operation in Active Background Mode
The MTIM suspends all counting until the MCU returns to normal user operating mode. Counting resumes
from the suspended value as long as an MTIM reset did not occur (TRST written to a 1 or any value is
written to the MTIMMOD register).
MC9RS08KA2 Series Data Sheet, Rev. 2
88
Freescale Semiconductor