C8051F388 Datasheet, PDF (229/285 Pages) –

C8051F388/9/A/B
Figure 25.2. T0 Mode 2 Block Diagram
25.1.4. Mode 3: Two 8-bit Counter/Timers (Timer 0 Only)
In Mode 3, Timer 0 is configured as two separate 8-bit counter/timers held in TL0 and TH0. The
counter/timer in TL0 is controlled using the Timer 0 control/status bits in TCON and TMOD: TR0, C/T0,
GATE0 and TF0. TL0 can use either the system clock or an external input signal as its timebase. The TH0
register is restricted to a timer function sourced by the system clock or prescaled clock. TH0 is enabled
using the Timer 1 run control bit TR1. TH0 sets the Timer 1 overflow flag TF1 on overflow and thus controls
the Timer 1 interrupt.
Timer 1 is inactive in Mode 3. When Timer 0 is operating in Mode 3, Timer 1 can be operated in Modes 0,
1 or 2, but cannot be clocked by external signals nor set the TF1 flag and generate an interrupt. However,
the Timer 1 overflow can be used to generate baud rates or overflow conditions for other peripherals.
While Timer 0 is operating in Mode 3, Timer 1 run control is handled through its mode settings. To run
Timer 1 while Timer 0 is in Mode 3, set the Timer 1 Mode as 0, 1, or 2. To disable Timer 1, configure it for
Mode 3.
Rev. 1.1
229