AT90S8535-8AC Atmel, AT90S8535-8AC Datasheet - Page 74
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AT90S8535-8AC
Manufacturer Part Number
AT90S8535-8AC
Description
IC MCU 8K FLSH 8MHZ A/D 44TQFP
Manufacturer
Atmel
Series
AVR® 90Sr
Specifications of AT90S8535-8AC
Core Processor
AVR
Core Size
8-Bit
Speed
8MHz
Connectivity
SPI, UART/USART
Peripherals
Brown-out Detect/Reset, POR, PWM, WDT
Number Of I /o
32
Program Memory Size
8KB (4K x 16)
Program Memory Type
FLASH
Eeprom Size
512 x 8
Ram Size
512 x 8
Voltage - Supply (vcc/vdd)
4 V ~ 6 V
Data Converters
A/D 8x10b
Oscillator Type
Internal
Operating Temperature
0°C ~ 70°C
Package / Case
44-TQFP, 44-VQFP
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
AT90S8535-8AC
Manufacturer:
ROHM
Quantity:
6 934
Part Number:
AT90S8535-8AC
Manufacturer:
ATMEL/爱特梅尔
Quantity:
20 000
Scanning Multiple
Channels
ADC Noise Canceling
Techniques
74
AT90S/LS8535
• ADC9..0: ADC Conversion result
These bits represent the result from the conversion. $000 represents analog ground and
$3FF represents the selected reference voltage minus one LSB.
Since change of analog channel always is delayed until a conversion is finished, the
Free Running Mode can be used to scan multiple channels without interrupting the con-
verter. Typically, the ADC Conversion Complete interrupt will be used to perform the
channel shift. However, the user should take the following fact into consideration: The
interrupt triggers once the result is ready to be read. In Free Running Mode, the next
conversion will start immediately when the interrupt triggers. If ADMUX is changed after
the interrupt triggers, the next conversion has already started and the old setting is
used.
Digital circuitry inside and outside the AT90S8535 generates EMI that might affect the
accuracy of analog measurements. If conversion accuracy is critical, the noise level can
be reduced by applying the following techniques:
1. The analog part of the AT90S8535 and all analog components in the application
2. Keep analog signal paths as short as possible. Make sure analog tracks run over
3. The AV
4. Use the ADC noise canceler function to reduce induced noise from the CPU.
5. If some Port A pins are used as digital outputs, it is essential that these do not
Figure 50. ADC Power Connections
should have a separate analog ground plane on the PCB. This ground plane is
connected to the digital ground plane via a single point on the PCB.
the analog ground plane and keep them well away from high-speed switching
digital tracks.
voltage via an LC network as shown in Figure 50.
switch while a conversion is in progress.
CC
pin on the AT90S8535 should be connected to the digital V
1
44
43
42
41
40
39
38
37
36
35
34
33
32
PA4 (ADC4)
PA5 (ADC5)
PA6 (ADC6)
PA7 (ADC7)
AREF
AGND
AVCC
PC0
CC
supply
1041H–11/01