Rev. 1.1
247
C8051F410/1/2/3
SFR Definition 24.13. TMR3CN: Timer 3 Control
Bit7:
TF3H: Timer 3 High Byte Overflow Flag.
Set by hardware when the Timer 3 high byte overflows from 0xFF to 0x00. In 16 bit mode,
this will occur when Timer 3 overflows from 0xFFFF to 0x0000. When the Timer 3 interrupt is
enabled, setting this bit causes the CPU to vector to the Timer 3 interrupt service routine.
TF3H is not automatically cleared by hardware and must be cleared by software.
Bit6:
TF3L: Timer 3 Low Byte Overflow Flag.
Set by hardware when the Timer 3 low byte overflows from 0xFF to 0x00. When this bit is
set, an interrupt will be generated if TF3LEN is set and Timer 3 interrupts are enabled. TF3L
will set when the low byte overflows regardless of the Timer 3 mode. This bit is not automat-
ically cleared by hardware.
Bit5:
TF3LEN: Timer 3 Low Byte Interrupt Enable.
This bit enables/disables Timer 3 Low Byte interrupts. If TF3LEN is set and Timer 3 inter-
rupts are enabled, an interrupt will be generated when the low byte of Timer 3 overflows.
This bit should be cleared when operating Timer 3 in 16-bit mode.
0: Timer 3 Low Byte interrupts disabled.
1: Timer 3 Low Byte interrupts enabled.
Bit4:
TF3CEN: Timer 3 Capture Enable.
0: Timer 3 capture mode disabled.
1: Timer 3 capture mode enabled.
Bit3:
T3SPLIT: Timer 3 Split Mode Enable.
When this bit is set, Timer 3 operates as two 8-bit timers with auto-reload.
0: Timer 3 operates in 16-bit auto-reload mode.
1: Timer 3 operates as two 8-bit auto-reload timers.
Bit2:
TR3: Timer 3 Run Control.
This bit enables/disables Timer 3. In 8-bit mode, this bit enables/disables TMR3H only;
TMR3L is always enabled in this mode.
0: Timer 3 disabled.
1: Timer 3 enabled.
Bit1:
T3RCLK: Timer 3 Capture Mode.
This bit controls the Timer 3 capture source when TF3CEN=1. If T3XCLK = 1 and T3ML
(CKCON.6) = 0, this bit also controls the clock source for Timer 3.
0: Capture every smaRTClock clock/8. If T3XCLK = 1 and T3ML (CKCON.6) = 0, count at
external oscillator/8.
1: Capture every external oscillator/8. If T3XCLK = 1 and T3ML (CKCON.6) = 0, count at
smaRTClock clock/8.
Bit0:
T3XCLK: Timer 3 External Clock Select.
This bit selects the external clock source for Timer 3. If Timer 3 is in 8-bit mode, this bit
selects the external oscillator clock source for both timer bytes. However, the Timer 3 Clock
Select bits (T3MH and T3ML in register CKCON) may still be used to select between the
external clock and the system clock for either timer.
0: Timer 3 external clock selection is the system clock divided by 12.
1: Timer 3 external clock uses the clock defined by the T3RCLK bit.
R/W
Reset Value
TF3H
TF3L
TF3LEN
TF3CEN
T3SPLIT
TR3
T3RCLK
T3XCLK
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address:
0x91