Maxim Integrated High-Speed Microcontroller Users Guide: DS80C390 Supplement - Manual (Page 19)

High-Speed Microcontroller User’s Guide: DS80C390 Supplement
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TIMER MODE CONTROL (TMOD)
7 6 5 4 3 2 1 0
SFR 89h GATE C/ T M1 M0 GATE C/ T M1 M0
RW-0 RW-0 RW-0 RW-0 RW-0 RW-0 RW-0 RW-0
R = Unrestricted Read, W = Unrestricted Write, -n = Value after Reset
GATE
Bit 7 Timer 1 Gate Control. This bit enable/disables the ability of Timer 1 to
increment.
0 = Timer 1 will clock when TR1=1, regardless of the state of 1 INT .
1 = Timer 1 will clock only when TR1=1 and 1 INT =1.
C/ T
Bit 6 Timer 1 Counter/Timer Select.
0 = Timer 1 is incremented by internal clocks.
1 = Timer 1 is incremented by pulses on T1 when TR1 (TCON.6) is 1.
M1, M0
Bits 5-4 Timer 1 Mode Select. These bits select the operating mode of Timer 1.
M1 M0 Mode
0
0 Mode 0: 8 bits with 5-bit prescale
0 1 Mode 1: 16 bits
1 0 Mode 2: 8 bits with auto-reload
1 1 Mode 3: Timer 1 is halted, but holds its count
GATE
Bit 3 Timer 0 Gate Control. This bit enables/disables that ability of Timer 0 to
increment.
0 = Timer 0 will clock when TR0=1, regardless of the state of 0 INT .
1 = Timer 0 will clock only when TR0=1 and 0 INT =1.
C/ T
Bit 2 Timer 0 Counter/Timer Select.
0 = Timer incremented by internal clocks.
1 = Timer 1 is incremented by pulses on T0 when TR0 (TCON.4) is 1.
M1, M0
Bits 1-0 Timer 0 Mode Select. These bits select the operating mode of Timer 0.
When Timer 0 is in mode 3, TL0 is started/stopped by TR0 and TH0 is
started/stopped by TR1. Run control from Timer 1 is then provided by the
Timer 1 mode selection.
M1 M0
Mode
0 0 Mode 0: 8 bits with 5-bit prescale
0 1 Mode 1: 16 bits
1 0 Mode 2: 8 bits with auto-reload
1 1 Mode 3: Timer 0 is two 8-bit counters.