AT89C5122 ATMEL [ATMEL Corporation], AT89C5122 Datasheet - Page 153

• Manufacturer Part Number: AT89C5122
• Description: MICROCONTROLLER WITH USB AND SMART CARD READER INTERFACES
• Manufacturer: ATMEL [ATMEL Corporation]

Table 89. Timer/Counter Mode Control Register - TMOD (S:89h)
Reset Value = 0000 0000b
4202D–SCR–06/05
Bit Number
GATE1
7
6
5
4
3
2
1
0
7
Bit Mnemonic
GATE1
GATE0
C/T1#
C/T0#
M11
M01
M10
M00
C/T1#
6
Description
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
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
TH0 is an 8-bit Timer using Timer 1’s TR0 and TF0 bits.
0
0
1
1
M11
0
0
1
1
M11
5
M01
M00
0
1
0
1
0
1
0
1
Operating mode
Mode 0:8-bit Timer/Counter (TH1) with 5-bit prescaler (TL1).
Mode 1:16-bit Timer/Counter.
Mode 2:8-bit auto-reload Timer/Counter (TL1). Reloaded from TH1 at overflow.
Mode 3:Timer 1 halted. Retains count.
Operating mode
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). Reloaded from TH0 at overflow.
Mode 3:TL0 is an 8-bit Timer/Counter.
M01
4
GATE0
3
C/T0#
2
M10
1
M00
0
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