AT90PWM3-16SQ Atmel, AT90PWM3-16SQ Datasheet - Page 34

• Manufacturer Part Number: AT90PWM3-16SQ
• Description: IC AVR MCU FLASH 8K 32SOIC
• Manufacturer: Atmel
• Series: AVR® 90PWM Lightingr

Specifications of AT90PWM3-16SQ

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 27
• 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; D/A 1x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 105°C
• Package / Case: 32-SOIC (7.5mm Width)
• Processor Series: AT90PWMx
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 512 B
• Interface Type: SPI, USART
• Maximum Clock Frequency: 16 MHz
• Number Of Programmable I/os: 27
• Number Of Timers: 2
• Operating Supply Voltage: 2.7 V to 5.5 V
• Maximum Operating Temperature: + 105 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Development Tools By Supplier: ATAVRDRAGON, ATSTK500, ATSTK600, ATAVRISP2, ATAVRONEKIT, ATAVRFBKIT, ATAVRISP2
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit, 11 Channel
• On-chip Dac: 10 bit, 1 Channel
• For Use With: ATSTK600-SOIC - STK600 SOCKET/ADAPTER FOR SOICATAVRMC200 - KIT EVAL FOR AT90PWM3 ASYNCATAVRFBKIT - KIT DEMO BALLAST FOR AT90PWM2ATSTK520 - ADAPTER KIT FOR 90PWM
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

7.6
7.6.1
34
PLL
AT90PWM2/3/2B/3B
Internal PLL for PSC
Note that this oscillator is used to time EEPROM and Flash write accesses, and these write
times will be affected accordingly. If the EEPROM or Flash are written, do not calibrate to more
than 8.8 MHz. Otherwise, the EEPROM or Flash write may fail.
The CAL7 bit determines the range of operation for the oscillator. Setting this bit to 0 gives the
lowest frequency range, setting this bit to 1 gives the highest frequency range. The two fre-
quency ranges are overlapping, in other words a setting of OSCCAL = 0x7F gives a higher
frequency than OSCCAL = 0x80.
The CAL6..0 bits are used to tune the frequency within the selected range. A setting of 0x00
gives the lowest frequency in that range, and a setting of 0x7F gives the highest frequency in the
range. Incrementing CAL6..0 by 1 will give a frequency increment of less than 2% in the fre-
quency range 7.3 - 8.1 MHz.
To generate high frequency and accurate PWM waveforms, the ‘PSC’s need high frequency
clock input. This clock is generated by a PLL. To keep all PWM accuracy, the frequency factor of
PLL must be configurable by software. With a system clock of 8 MHz, the PLL output is 32Mhz
or 64Mhz.
The internal PLL in AT90PWM2/2B/3/3B generates a clock frequency that is 64x multiplied from
nominally 1 MHz input. The source of the 1 MHz PLL input clock is the output of the internal RC
Oscillator which is divided down to 1 MHz. See the
The PLL is locked on the RC Oscillator and adjusting the RC Oscillator via OSCCAL Register
will adjust the fast peripheral clock at the same time. However, even if the possibly divided RC
Oscillator is taken to a higher frequency than 1 MHz, the fast peripheral clock frequency satu-
rates at 70 MHz (worst case) and remains oscillating at the maximum frequency. It should be
noted that the PLL in this case is not locked any more with the RC Oscillator clock.
Therefore it is recommended not to take the OSCCAL adjustments to a higher frequency than 1
MHz in order to keep the PLL in the correct operating range. The internal PLL is enabled only
when the PLLE bit in the register PLLCSR is set. The bit PLOCK from the register PLLCSR is
set when PLL is locked.
Both internal 1 MHz RC Oscillator and PLL are switched off in Power-down and Standby sleep
modes
.
Table 7-9.
RC Osc
CKSEL
0011
3..0
SUT1..0
Start-up Times when the PLL is selected as system clock
00
01
10
11
Start-up Time from Power-down
and Power-save
16K CK
1K CK
1K CK
1K CK
Figure 7-4 on page
Additional Delay from Reset
35.
14CK + 64 ms
14CK + 4 ms
(V
CC
14CK
14CK
= 5.0V)
4317J–AVR–08/10