ATmega32A Atmel Corporation, ATmega32A Datasheet - Page 44

• Manufacturer Part Number: ATmega32A
• Manufacturer: Atmel Corporation

Specifications of ATmega32A

• Flash (kbytes): 32 Kbytes
• Pin Count: 44
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 32
• Ext Interrupts: 3
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Twi (i2c): 1
• Uart: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 2
• Eeprom (bytes): 1024
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 2.7 to 5.5
• Operating Voltage (vcc): 2.7 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 3
• Output Compare Channels: 4
• Input Capture Channels: 1
• Pwm Channels: 4
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

8155C–AVR–02/11
The WDP2, WDP1, and WDP0 bits determine the Watchdog Timer prescaling when the Watch-
dog Timer is enabled. The different prescaling values and their corresponding Timeout Periods
are shown in
Table 10-1.
The following code example shows one assembly and one C function for turning off the WDT.
The example assumes that interrupts are controlled (for example by disabling interrupts globally)
so that no interrupts will occur during execution of these functions.
Assembly Code Example
C Code Example
WDP2
0
0
0
0
1
1
1
1
WDT_off:
void WDT_off(void)
{
}
; reset WDT
wdr
; Write logical one to WDTOE and WDE
in
ori r16, (1<<WDTOE)|(1<<WDE)
out WDTCR, r16
; Turn off WDT
ldi r16, (0<<WDE)
out WDTCR, r16
ret
/* reset WDT */
_WDR();
/* Write logical one to WDTOE and WDE */
WDTCR |= (1<<WDTOE) | (1<<WDE);
/* Turn off WDT */
WDTCR = 0x00;
WDP1
r16, WDTCR
Table
0
0
1
1
0
0
1
1
Watchdog Timer Prescale Select
10-1.
WDP0
0
1
0
1
0
1
0
1
1,024K (1,048,576)
2,048K (2,097,152)
Oscillator Cycles
Number of WDT
128K (131,072)
256K (262,144)
512K (524,288)
16K (16,384)
32K (32,768)
64K (65,536)
Typical Time-out
at V
17.1ms
34.3ms
68.5ms
0.14s
0.27s
0.55s
CC
1.1s
2.2s
= 3.0V
ATmega32A
Typical Time-out
at V
16.3ms
32.5ms
CC
65ms
0.13s
0.26s
0.52s
1.0s
2.1s
= 5.0V
44