ATA6616-P3QW Atmel, ATA6616-P3QW Datasheet - Page 58

• Manufacturer Part Number: ATA6616-P3QW
• Description: TXRX MULTICHIP MOD LIN SIP 38QFN
• Manufacturer: Atmel
• Series: AVR® ATA66 LIN-SBCr

Specifications of ATA6616-P3QW

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: I²C, LIN, SPI, UART/USART, USI
• Peripherals: Brown-out Detect/Reset, POR, PWM, Temp Sensor, WDT
• Number Of I /o: 16
• Program Memory Size: 8KB (8K x 8)
• Program Memory Type: FLASH
• Eeprom Size: 512 x 8
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 11x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 38-VQFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

58
Atmel ATA6616/ATA6617
The clock switching is performed by a sequence of commands. First, the user (code) must
make sure that the new clock source is operating. Then the ‘Clock Source Switching’ com-
mand can be issued. Once this command has been successfully completed using the
‘Recover System Clock Source’ command, the user (code) may stop the previous clock
source. It is strongly recommended to run this sequence only once the interrupts have been
disabled. The user (code) is responsible for the correct implementation of the clock switching
sequence.
Here is a “light” C-code that describes such a sequence of commands.
Warning:
In the Atmel
at a given time. Moreover, the enables of the external clock and of the external low-frequency
oscillator are shared with the asynchronous timer.
C Code Example
void ClockSwiching (unsigned char clk
#define CLOCK
#define CLOCK
#define CLOCK
#define CLOCK
unsigned char previous
}
// Disable interrupts
// Save the current system clock source
// Enable the new clock source
// Wait for clock validity
// Switch clock source
// Wait for effective switching
// Shut down unneeded clock source
// Re-enable interrupts
temp = SREG; asm ("cli");
CLKCSR = 1 << CLKCCE;
CLKCSR = CLOCK
previous
CLKSELR = ((sut << 4 ) & 0x30) | (clk
CLKCSR = 1 << CLKCCE;
CLKCSR = CLOCK
while ((CLKCSR & (1 << CLKRDY)) == 0);
CLKCSR = 1 << CLKCCE;
CLKCSR = CLOCK
while (1){
}
if (previous_clk != (clk_number & 0x0F)) {
}
SREG = temp;
®
CLKCSR = 1 << CLKCCE;
CLKCSR = CLOCK
if ((CLKSELR & 0x0F) == (clk
CLKSELR = previous
CLKCSR = 1 << CLKCCE;
CLKCSR = CLOCK
ATtiny87/167, only one among the three external clock sources can be enabled
_
clk = CLKSELR & 0x0F;
_
_
_
_
RECOVER
ENABLE
SWITCH
DISABLE
_
_
_
RECOVER;
ENABLE;
SWITCH;
_
_
RECOVER;
DISABLE;
_
clk, temp;
0x05
0x02
0x04
0x01
_
clk;
_
number & 0x0F)) break;
_
number, unsigned char sut) {
_
number & 0x0F);
9132D–AUTO–12/10