at89c51re2-slsem ATMEL Corporation, at89c51re2-slsem Datasheet - Page 70

• Manufacturer Part Number: at89c51re2-slsem
• Description: At89c51re2 8-bit Flash Microcontroller
• Manufacturer: ATMEL Corporation

Mode 0 (13-bit Timer)
Figure 7. Timer/Counter x (x = 0 or 1) in Mode 0
Mode 1 (16-bit Timer)
Figure 8. Timer/Counter x (x = 0 or 1) in Mode 1
7663B–8051–03/07
INTx#
See the “Clock” section
INTx#
See the “Clock” section
CLOCK
CLOCK
FTx
Tx
FTx
Tx
TMOD reg
GATEx
TMOD reg
GATEx
÷ 6
÷ 6
TMOD reg
TMOD reg
C/Tx#
C/Tx#
Mode 0 configures Timer 0 as an 13-bit Timer which is set up as an 8-bit Timer (TH0
register) with a modulo 32 prescaler implemented with the lower five bits of TL0 register
(see Figure 7). The upper three bits of TL0 register are indeterminate and should be
ignored. Prescaler overflow increments TH0 register.
Mode 1 configures Timer 0 as a 16-bit Timer with TH0 and TL0 registers connected in
cascade (see Figure 8). The selected input increments TL0 register.
0
1
0
1
TCON reg
TCON reg
TRx
TRx
(8 bits)
(8 bits)
THx
THx
(8 bits)
(5 bits)
TLx
TLx
Overflow
Overflow
TCON reg
TCON reg
TFx
TFx
Timer x
Interrupt
Request
Timer x
Interrupt
Request
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