Motorola MC6805R Series Advance Information page 35

U1
~
Timer
Pin
Internal
ct>2
Clock
Ifosc+4)
fplN - Prescaler Input Frequency
fCIN-Counter Input Frequency
8
Timer Data Register !TOR)
8-Bit Counter
7-Bit Prescaler
Select
1 - - - - - - - - - - - 1 1
1-of-8
3
Timer Control Register Bits:
Set
TIR- Timer Interrupt Request Status
TIM - Timer Interrupt Mask
TIN - Timer Input Select
TIE- Timer External Input Enable
PSC - Prescaler Clear
PS2, PS1, PSO- Prescaler Select
Timer Control Register ITCR)
Mask Option Register Bits:
ClK - Clock Oscillator Type
TOPT - Timer Mask/ Programmable Option
ClS - Timer Clock Source
ITIE) - (Timer External Input Enable)
SNM - Secure/Non-Secure Mode Option
P2, P1, PO- Prescaler Option
NOTES: The TOPT bit in the mask option register selects whether the timer is software programmable via the timer control register or emulates
the mask programmable parts via the MOR PROM byte.
The TIE bit in the mask option register is not used if MOR TOPT = 1 (MC6805P2 emulation). It sets the intial value of TCR TIE if MOR
TOPT=O.
Figure 5-4. MC68705R5/MC68705U5 Timer Block Diagram
Timer