AT90PWM3B-16SU Atmel, AT90PWM3B-16SU Datasheet - Page 198

• Manufacturer Part Number: AT90PWM3B-16SU
• Description: IC MCU AVR RISC 8K FLASH 32-SOIC
• Manufacturer: Atmel
• Series: AVR® 90PWM Lightingr

Specifications of AT90PWM3B-16SU

• 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: 11-ch x 10-bit
• On-chip Dac: 1-chx10-bit
• Controller Family/series: AVR PWM
• Eeprom Memory Size: 512Byte
• Ram Memory Size: 512Byte
• Cpu Speed: 16MHz
• Rohs Compliant: Yes
• For Use With: ATSTK600-SOIC - STK600 SOCKET/ADAPTER FOR SOIC770-1007 - ISP 4PORT ATMEL AVR MCU SPI/JTAGATAVRMC200 - KIT EVAL FOR AT90PWM3 ASYNCATAVRFBKIT - KIT DEMO BALLAST FOR AT90PWM2ATAVRISP2 - PROGRAMMER AVR IN SYSTEMATSTK520 - ADAPTER KIT FOR 90PWM
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

18.8.2
198
AT90PWM2/3/2B/3B
Asynchronous Data Recovery
figure), to decide if a valid start bit is received. If two or more of these three samples have logical
high levels (the majority wins), the start bit is rejected as a noise spike and the Receiver starts
looking for the next high to low-transition. If however, a valid start bit is detected, the clock recov-
ery logic is synchronized and the data recovery can begin. The synchronization process is
repeated for each start bit.
When the receiver clock is synchronized to the start bit, the data recovery can begin. The data
recovery unit uses a state machine that has 16 states for each bit in Normal mode and eight
states for each bit in Double Speed mode.
the parity bit. Each of the samples is given a number that is equal to the state of the recovery
unit.
Figure 18-7. Sampling of Data and Parity Bit
The decision of the logic level of the received bit is taken by doing a majority voting of the logic
value to the three samples in the center of the received bit. The center samples are emphasized
on the figure by having the sample number inside boxes. The majority voting process is done as
follows: If two or all three samples have high levels, the received bit is registered to be a logic 1.
If two or all three samples have low levels, the received bit is registered to be a logic 0. This
majority voting process acts as a low pass filter for the incoming signal on the RxD pin. The
recovery process is then repeated until a complete frame is received. Including the first stop bit.
Note that the Receiver only uses the first stop bit of a frame.
Figure 18-8
of the next frame.
Figure 18-8. Stop Bit Sampling and Next Start Bit Sampling
The same majority voting is done to the stop bit as done for the other bits in the frame. If the stop
bit is registered to have a logic 0 value, the Frame Error (FE) flag will be set.
A new high to low transition indicating the start bit of a new frame can come right after the last of
the bits used for majority voting. For Normal Speed mode, the first low level sample can be at
point marked (A) in
(B). (C) marks a stop bit of full length. The early start bit detection influences the operational
range of the Receiver.
(U2Xn = 0)
(U2Xn = 1)
(U2Xn = 0)
(U2Xn = 1)
Sample
Sample
Sample
Sample
RxDn
RxDn
shows the sampling of the stop bit and the earliest possible beginning of the start bit
Figure
1
1
1
1
18-8. For Double Speed mode the first low level must be delayed to
2
2
3
2
3
2
4
4
5
3
5
3
Figure 18-7
6
6
7
4
7
4
STOP 1
8
8
BIT x
shows the sampling of the data bits and
9
5
9
5
10
10
0/1
(A)
11
6
6
0/1
12
0/1
0/1
(B)
13
7
14
15
8
16
4317J–AVR–08/10
(C)
1
1