AT89LP216 Atmel Corporation, AT89LP216 Datasheet - Page 28

• Manufacturer Part Number: AT89LP216
• Manufacturer: Atmel Corporation

Specifications of AT89LP216

• Flash (kbytes): 2 Kbytes
• Max. Operating Frequency: 20 MHz
• Cpu: 8051-1C
• Max I/o Pins: 14
• Spi: 1
• Uart: 1
• Sram (kbytes): 0.125
• Operating Voltage (vcc): 2.4 to 5.5
• Timers: 2
• Isp: SPI/OCD
• Watchdog: Yes

14.2
28
Mode 1 – 16-bit Auto-Reload Timer/Counter
AT89LP216
Figure 14-1. 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). The INT0 and INT1 pins are shared with the
XTAL oscillator. They may only be used for the GATE function when using the internal RC oscil-
lator as the system clock.
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
overflow flag bit in TCON is set. See
gives the full 16-bit timer period compatible with the standard 8051. Mode 1 operation is the
same for Timer/Counter 0.
Figure 14-2. Timer/Counter 1 Mode 1: 16-bit Auto-reload
INT1 Pin
T1 Pin
INT1 Pin
GATE
OSC
GATE
T1 Pin
OSC
Mode 1:
TR1
÷TPS
TR1
÷TPS
C/T = 0
C/T = 1
Time-out Period
C/T = 0
C/T =1
Control
Control
Figure
Figure
14-2. The reload registers default to 0000H, which
=
14-1. There are two different GATE bits, one for
(
---------------------------------------------------------
Oscillator Frequency
65536
(8 Bits)
(8 Bits)
(8 Bits)
TL1
RL1
TL1
–
{
RH0 RL0
(8 Bits)
(8 Bits)
RH1
TH1
(8 Bits)
,
TH1
PSC1
}
)
×
Reload
(
TF1
TPS
TF1
+
1
3621E–MICRO–11/10
)
Interrupt
Interrupt