T89C5115 ATMEL Corporation, T89C5115 Datasheet - Page 54

• Manufacturer Part Number: T89C5115
• Description: Low Pin Count 8-bit MCU with A/D Converter and 16-Kbytes of Flash Memory
• Manufacturer: ATMEL Corporation

54
T89C5115
Table 32. TMOD Register
TMOD (S:89h)
Timer/Counter Mode Control Register
Notes:
Reset Value = 0000 0000b
Number
GATE1
Bit
7
7
6
5
4
3
2
1
0
1. Reloaded from TH1 at overflow.
2. Reloaded from TH0 at overflow.
Mnemonic Description
GATE1
GATE0
C/T1#
C/T1#
C/T0#
M11
M01
M10
M00
Bit
6
Timer 1 Gating Control Bit
Clear to enable Timer 1 whenever TR1 bit is set.
Set to enable Timer 1 only while INT1# pin is high and TR1 bit is set.
Timer 1 Counter/Timer Select Bit
Clear for Timer operation: Timer 1 counts the divided-down system clock.
Set for Counter operation: Timer 1 counts negative transitions on external pin T1.
Timer 1 Mode Select Bits
M11 M01 Operating mode
Timer 0 Gating Control Bit
Clear to enable Timer 0 whenever TR0 bit is set.
Set to enable Timer/Counter 0 only while INT0# pin is high and TR0 bit is set.
Timer 0 Counter/Timer Select Bit
Clear for Timer operation: Timer 0 counts the divided-down system clock.
Set for Counter operation: Timer 0 counts negative transitions on external pin T0.
Timer 0 Mode Select Bit
M10 M00 Operating mode
TH0 is an 8-bit Timer using Timer 1’s TR0 and TF0 bits.
0
0
1
1
0
0
1
1
M11
5
0
1
1
0
0
1
0
1
Mode 0: 8-bit Timer/Counter (TH1) with 5-bit prescaler (TL1).
Mode 1: 16-bit Timer/Counter.
Mode 3: Timer 1 halted. Retains count.
Mode 2: 8-bit auto-reload Timer/Counter (TL1).
Mode 0: 8-bit Timer/Counter (TH0) with 5-bit prescaler (TL0).
Mode 1: 16-bit Timer/Counter.
Mode 2: 8-bit auto-reload Timer/Counter (TL0).
Mode 3: TL0 is an 8-bit Timer/Counter.
M01
4
GATE0
3
C/T0#
2
(1)
(2)
M10
1
4128A–8051–04/02
M00
0