AT90CAN64 Atmel Corporation, AT90CAN64 Datasheet - Page 59
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AT90CAN64
Manufacturer Part Number
AT90CAN64
Description
Manufacturer
Atmel Corporation
Specifications of AT90CAN64
Flash (kbytes)
64 Kbytes
Pin Count
64
Max. Operating Frequency
16 MHz
Cpu
8-bit AVR
# Of Touch Channels
16
Hardware Qtouch Acquisition
No
Max I/o Pins
53
Ext Interrupts
8
Usb Speed
No
Usb Interface
No
Spi
1
Twi (i2c)
1
Uart
2
Can
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)
4
Eeprom (bytes)
2048
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
4
Output Compare Channels
8
Input Capture Channels
2
Pwm Channels
7
32khz Rtc
Yes
Calibrated Rc Oscillator
Yes
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Price
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7.4
7.4.1
7.4.2
7679H–CAN–08/08
Timed Sequences for Changing the Configuration of the Watchdog Timer
Safety Level 1
Safety Level 2
The following code example shows one assembly and one C function for turning off the WDT.
The example assumes that interrupts are controlled (e.g. by disabling interrupts globally) so that
no interrupts will occur during execution of these functions.
Note:
The sequence for changing configuration differs slightly between the two safety levels. Separate
procedures are described for each level.
In this mode, the Watchdog Timer is initially disabled, but can be enabled by writing the WDE bit
to 1 without any restriction. A timed sequence is needed when changing the Watchdog Time-out
period or disabling an enabled Watchdog Timer. To disable an enabled Watchdog Timer, and/or
changing the Watchdog Time-out, the following procedure must be followed:
In this mode, the Watchdog Timer is always enabled, and the WDE bit will always read as one. A
timed sequence is needed when changing the Watchdog Time-out period. To change the
Watchdog Time-out, the following procedure must be followed:
Assembly Code Example
C Code Example
1. In the same operation, write a logic one to WDCE and WDE. A logic one must be writ-
2. Within the next four clock cycles, in the same operation, write the WDE and WDP bits
1. In the same operation, write a logical one to WDCE and WDE. Even though the WDE
2. Within the next four clock cycles, in the same operation, write the WDP bits as desired,
WDT_off:
void WDT_off(void)
{
}
ten to WDE regardless of the previous value of the WDE bit.
as desired, but with the WDCE bit cleared.
always is set, the WDE must be written to one to start the timed sequence.
but with the WDCE bit cleared. The value written to the WDE bit is irrelevant.
; Write logical one to WDCE and WDE
ldi
sts
; Turn off WDT
ldi
sts
ret
/* Write logical one to WDCE and WDE */
WDTCR = (1<<WDCE) | (1<<WDE);
/* Turn off WDT */
WDTCR = 0x00;
1. The example code assumes that the part specific header file is included.
r16, (1<<WDCE)|(1<<WDE)
WDTCR, r16
r16, (0<<WDE)
WDTCR, r16
(1)
(1)
AT90CAN32/64/128
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