AT89LP428 Atmel Corporation, AT89LP428 Datasheet - Page 46

• Manufacturer Part Number: AT89LP428
• Manufacturer: Atmel Corporation

Specifications of AT89LP428

• Flash (kbytes): 4 Kbytes
• Max. Operating Frequency: 25 MHz
• Cpu: 8051-1C
• Max I/o Pins: 30
• Spi: 1
• Uart: 1
• Sram (kbytes): 0.75
• Eeprom (bytes): 512
• Self Program Memory: IAP
• Operating Voltage (vcc): 2.4 to 5.5
• Timers: 3
• Isp: SPI/OCD
• Watchdog: Yes

Table 11-3.
46
TMOD Address = 089H
Not Bit Addressable
Symbol
GATE1
C/T1
T1M1
T1M0
GATE0
C/T0
T0M1
T0M0
Bit
AT89LP428/828
GATE1
Function
Timer 1 Gating Control. When set. Timer/Counter 1 is enabled only while INT1 pin is high and TR1 control pin is set.
When cleared, Timer 1 is enabled whenever TR1 control bit is set.
Timer or Counter Selector 1. Cleared for Timer operation (input from internal system clock). Set for Counter operation
(input from T1 input pin). C/T1 must be zero when using Timer 1 in PWM mode.
Mode
Timer 0 Gating Control. When set. Timer/Counter 0 is enabled only while INT0 pin is high and TR0 control pin is set.
When cleared, Timer 0 is enabled whenever TR0 control bit is set.
Timer or Counter Selector 0. Cleared for Timer operation (input from internal system clock). Set for Counter operation
(input from T0 input pin). C/T0 must be zero when using Timer 0 in PWM mode.
Mode
7
TMOD – Timer/Counter Mode Control Register
0
1
2
3
0
1
2
3
T1M1
T0M1
0
0
1
1
0
0
1
1
C/T1
6
T1M0
T0M0
0
1
0
1
0
1
0
1
Timer 1 Operation
Variable 9 – 16-bit Timer mode. 8-bit Timer/Counter TH1 with TL1 as 1- to 8-bit prescaler.
16-bit Auto-reload mode. TH1 and TL1 are cascaded to form a 16-bit Timer/Counter that is
reloaded with RH1 and RL1 each time it overflows.
8-bit Auto-reload mode. 8-bit Timer/Counter TL1 is reloaded from TH1 each time it overflows.
Timer/Counter 1 is stopped
Timer 0 Operation
Variable 9 – 16-bit Timer Mode. 8-bit Timer/Counter TH0 with TL0 as 1- to 8-bit prescaler.
16-bit Auto-reload mode. TH0 and TL0 are cascaded to form a 16-bit Timer/Counter that is
reloaded with RH0 and RL0 each time it overflows.
8-bit Auto-reload mode. 8-bit Timer/Counter TL0 is reloaded from TH0 each time it overflows.
Split Timer Mode. TL0 is an 8-bit Timer/Counter controlled by the standard Timer 0 control
bits. TH0 is an 8-bit timer only controlled by Timer 1 control bits.
T1M1
5
T1M0
4
GATE0
3
C/T0
2
Reset Value = 0000 0000B
T0M0
1
T0M1
0
3654A–MICRO–8/09