DS80C390_00 Datasheet, PDF (65/155 Pages) Dallas Semiconductor – High-Speed Microcontroller User’s Guide Supplement

Timer 2 Mode (T2MOD)
7
6
SFR C9h
1
1
R-1
R-1
DS80C390 High-Speed Microcontroller User’s Guide Supplement
5
4
3
2
1
0
1
D13T1 D13T2
1
T2OE DCEN
R-1
RW-0 RW-0
R-1
RW-0 RW-0
R=Unrestricted Read, W= Unrestricted Write, -n=Value after Reset
Bits 7-5
D13T1
Bit 4
D13T2
Bit 3
Bit 2
T2OE
Bit 1
DCEN
Bit 0
Reserved.
Divide by Thirteen Clock Option For Timer 1. The D13T1 bit provides an
alternate clock source to the Timer 1 in place of the normal external T1 input pin.
When D13T1 is cleared to 0 (the default Reset state), the clock source for Timer
1 is supplied through the standard T1 external input pin, the divide by 12 of the
oscillator (T1M = 0) or the divide by 4 of the oscillator (T1M = 1), as controlled
by T1M and C/ T . When D13T1 is set to a 1 the clock source for Timer 1 is
supplied through a separate divide by 13 of the crystal oscillator independent of
T1M. The C/ T bit must also be programmed to a 1 to select the divide by 13
counter.
Divide by Thirteen Clock Option For Timer 2. The D13T2 bit provides an
alternate clock source to the Timer 2 in place of the normal external T2 input pin.
When D13T2 is cleared to 0 (the default Reset state), the clock source for Timer
2 is supplied through the standard T2 external input pin, the divide by 12 of the
oscillator (T2M = 0) or the divide by 4 of the oscillator (T2M = 1), as controlled
by T2M and C/ T2 . When D13T2 is set to a 1 the clock source for Timer 2 is
supplied through a separate divide by 13 of the crystal oscillator independent of
T2M. The C/ T2 bit must also be programmed to a 1 to select the divide by 13
counter.
Reserved.
Timer 2 Output Enable. This bit enables/disables the clock output function of
the T2 pin (P1.0). 0 = The T2 pin functions as either a standard port pin or as a
counter input for timer 2. 1 = Timer 2 will drive the T2 pin with a clock output if
C/T2=0. Also, timer 2 rollovers will not cause interrupts.
Down Count Enable. This bit, in conjunction with the T2EX pin, controls the
direction that timer 2 counts in 16-bit auto-reload mode.
DCEN
T2EX
DIRECTION
1
1
Up
1
0
Down
0
X
Up
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