at89lp2052-20xi ATMEL Corporation, at89lp2052-20xi Datasheet - Page 24

• Manufacturer Part Number: at89lp2052-20xi
• Description: At89lp2052 8-bit Microcontroller With 2/4-kbyte Flash
• Manufacturer: ATMEL Corporation

16.2
24
Mode 1
AT89LP2052/LP4052
a control bit in the Special Function Register TCON. GATE is in TMOD. The 13-bit register con-
sists of all 8 bits of TH1 and the lower 5 bits of TL1. The upper 3 bits of TL1 are indeterminate
and should be ignored. Setting the run flag (TR1) does not clear the registers. See
Figure 16-1. Timer/Counter 1 Mode 0: Variable Width Counter
Mode 0 operation is the same for Timer 0 as for Timer 1, except that TR0, TF0 and INT0 replace
the corresponding Timer 1 signals in
Timer 1 (TMOD.7) and one for Timer 0 (TMOD.3).
In Mode 1 the Timers are configured for 16-bit auto-reload. The Timer register is run with all 16
bits. The 16-bit reload value is stored in the high and low reload registers (RH1/RL1). The clock
is applied to the combined high and low timer registers (TH1/TL1). As clock pulses are received,
the timer counts up: 0000H, 0001H, 0002H, etc. An overflow occurs on the FFFFH-to-0000H
transition, upon which the timer register is reloaded with the value from RH1/RL1 and the over-
flow flag bit in TCON is set. See
the full 16-bit timer period compatible with the standard 8051. Mode 1 operation is the same for
Timer/Counter 0.
Figure 16-2. Timer/Counter 1 Mode 1: 16-bit Auto-Reload
INT1 Pin
INT1 Pin
T1 Pin
GATE
OSC
GATE
T1 Pin
OSC
TR1
TR1
C/T = 0
C/T = 1
C/T = 0
C/T =1
Figure
Control
Control
Figure
16-2. The reload registers default to 0000H, which gives
16-1. There are two different GATE bits, one for
(8 Bits)
TL1
(8 Bits)
(8 Bits)
RL1
TL1
(8 Bits)
(8 Bits)
(8 Bits)
RH1
TH1
TH1
PSC1
Reload
TF1
TF1
3547H–MICRO–5/07
Figure
Interrupt
Interrupt
16-1.