4501_M Datasheet, PDF (140/212 Pages) Renesas Technology Corp – 4-BIT CISC SINGLE-CHIP MICROCOMPUTER 4500 SERIES

4501 Group
APPLICATION
2.3 Timers
(3) Timer control register W2
The timer 2 count source selection bits are assigned to bits 0 and 1, the timer 1 count auto-stop
circuit control bit is assigned to bit 2 and the timer 2 control bit is assigned to bit 3.
Set the contents of this register through register A with the TW2A instruction. The TAW2 instruction
can be used to transfer the contents of register W2 to register A.
Table 2.3.3 shows the timer control register W2.
Table 2.3.3 Timer control register W2
Timer control register W2
at reset : 00002 at RAM back-up : state retained R/W
W23 _{Timer 2 control bit}
0 Stop (state retained)
1 Operating
W22 ^{Timer 1 count auto-stop circuit 0 Count auto-stop circuit not selected}
control bit (Note 2)
1 Count auto-stop circuit selected
W21 W20
Count source
W21
W20
0
Timer 2 count source selection ₀
bits
1
1
0 Timer 1 underflow signal
1 Prescaler output (ORCLK)
0 CNTR input
1 System clock
Notes 1: “R” represents read enabled, and “W” represents write enabled.
2: This function is valid only when the timer 1 count start synchronous circuit is selected.
(4) Timer control register W6
The P12/CNTR function selection bit is assigned to bit 0 and the CNTR output control bit is assigned
to bit 1.
Set the contents of this register through register A with the TW6A instruction. The TAW6 instruction
can be used to transfer the contents of register W6 to register A.
Table 2.3.4 shows the timer control register W6.
Table 2.3.4 Timer control register W6
Timer control register W6
at reset : 00002 at RAM back-up : state retained R/W
W63 Not used
0
This bit has no function, but read/write is enabled.
1
W62 Not used
0
This bit has no function, but read/write is enabled.
1
W61 CNTR output control bit
0 Timer 1 underflow signal divided by 2 output
1 Timer 2 underflow signal divided by 2 output
0 P12 (I/O) / CNTR input (Note 2)
W60 P12/CNTR function selection bit _{1 P12 (input) / CNTR I/O (Note 2)}
Notes 1: “R” represents read enabled, and “W” represents write enabled.
2: The CNTR input is valid only when the CNTR input is selected for the timer 2 count source.
3: When timer is used, W63 and W62 are not used.
Rev.2.01 Feb 07, 2005
REJ09B0192-0201
2-23