C8051F124-GQR Datasheet, PDF (321/350 Pages) Silicon Laboratories – Mixed Signal ISP Flash MCU Family

C8051F120/1/2/3/4/5/6/7
C8051F130/1/2/3
SFR Definition 23.8. TMRnCN: Timer 2, 3, and 4 Control
R/W
R/W
R/W
TFn
EXFn
-
R/W
R/W
-
EXENn
Bit7
Bit6
Bit5
Bit4
Bit3
SFR Address: TMR2CN:0xC8;TMR3CN:0xC8;TMR4CN:0xC8
SFR Page: TMR2CN: page 0;TMR3CN: page 1;TMR4CN: page 2
R/W
TRn
Bit2
R/W
C/Tn
Bit1
R/W
CP/RLn
Bit0
Reset Value
00000000
Bit
Addressable
Bit7:
Bit6:
Bit5–4:
Bit3:
Bit2:
Bit1:
Bit0:
TFn: Timer 2, 3, and 4 Overflow/Underflow Flag.
Set by hardware when either the Timer overflows from 0xFFFF to 0x0000, underflows from
the value placed in RCAPnH:RCAPnL to 0xFFFF (in Auto-reload Mode), or underflows from
0x0000 to 0xFFFF (in Capture Mode). When the Timer interrupt is enabled, setting this bit
causes the CPU to vector to the Timer interrupt service routine. This bit is not automatically
cleared by hardware and must be cleared by software.
EXFn: Timer 2, 3, or 4 External Flag.
Set by hardware when either a capture or reload is caused by a high-to-low transition on the
TnEX input pin and EXENn is logic 1. When the Timer interrupt is enabled, setting this bit
causes the CPU to vector to the Timer Interrupt service routine. This bit is not automatically
cleared by hardware and must be cleared by software.
Reserved.
EXENn: Timer 2, 3, and 4 External Enable.
Enables high-to-low transitions on TnEX to trigger captures, reloads, and control the direc-
tion of the timer/counter (up or down count). If DCENn = 1, TnEX will determine if the timer
counts up or down when in Auto-reload Mode. If EXENn = 1, TnEX should be configured as
a digital input.
0: Transitions on the TnEX pin are ignored.
1: Transitions on the TnEX pin cause capture, reload, or control the direction of timer count
(up or down) as follows:
Capture Mode: ‘1’-to-’0’ Transition on TnEX pin causes RCAPnH:RCAPnL to capture timer
value.
Auto-Reload Mode:
DCENn = 0: ‘1’-to-’0’ transition causes reload of timer and sets the EXFn Flag.
DCENn = 1: TnEX logic level controls direction of timer (up or down).
TRn: Timer 2, 3, and 4 Run Control.
This bit enables/disables the respective Timer.
0: Timer disabled.
1: Timer enabled and running/counting.
C/Tn: Counter/Timer Select.
0: Timer Function: Timer incremented by clock defined by TnM1:TnM0
(TMRnCF.4:TMRnCF.3).
1: Counter Function: Timer incremented by high-to-low transitions on external input pin.
CP/RLn: Capture/Reload Select.
This bit selects whether the Timer functions in capture or auto-reload mode.
0: Timer is in Auto-Reload Mode.
1: Timer is in Capture Mode.
Note: Timer 3 and Timer 2 share the T2 and T2EX pins.
Rev. 1.4
321