ATMEGA128RFA1-ZU Atmel, ATMEGA128RFA1-ZU Datasheet - Page 420

• Manufacturer Part Number: ATMEGA128RFA1-ZU
• Description: IC AVR MCU 2.4GHZ XCEIVER 64QFN
• Manufacturer: Atmel
• Series: ATMEGAr

Specifications of ATMEGA128RFA1-ZU

• Frequency: 2.4GHz
• Data Rate - Maximum: 2Mbps
• Modulation Or Protocol: 802.15.4 Zigbee
• Applications: General Purpose
• Power - Output: 3.5dBm
• Sensitivity: -100dBm
• Voltage - Supply: 1.8 V ~ 3.6 V
• Current - Receiving: 12.5mA
• Current - Transmitting: 14.5mA
• Data Interface: PCB, Surface Mount
• Memory Size: 128kB Flash, 4kB EEPROM, 16kB RAM
• Antenna Connector: PCB, Surface Mount
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-VFQFN, Exposed Pad
• Rf Ic Case Style: QFN
• No. Of Pins: 64
• Supply Voltage Range: 1.8V To 3.6V
• Operating Temperature Range: -40°C To +85°C
• Svhc: No SVHC (15-Dec-2010)
• Rohs Compliant: Yes
• Processor Series: ATMEGA128x
• Core: AVR8
• Data Bus Width: 8 bit
• Program Memory Type: Flash
• Program Memory Size: 128 KB
• Data Ram Size: 16 KB
• Interface Type: JTAG
• Maximum Clock Frequency: 16 MHz
• Number Of Programmable I/os: 38
• Number Of Timers: 6
• Operating Supply Voltage: 1.8 V to 3.6 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Development Tools By Supplier: ATAVR128RFA1-EK1
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

27.6.3 ADC Voltage Reference
27.7 ADC Noise Canceller
420
ATmega128RFA1
Figure 27-10. ADC Timing Diagram, Changing MUXn during a Conversion
The reference voltage for the ADC (V
Single ended channels that exceed V
REFSn bits in the ADMUX register as either AVDD (1.8V), internal 1.5V or 1.6V
reference or an external voltage at the AREF pin.
AVDD is connected to the ADC through a passive switch. The internal 1.5V and 1.6V
references are generated from a bandgap reference (VBG) through an amplifier. In
either case, the external AREF pin is directly connected to the ADC and the reference
voltage can be measured at the AREF pin with a high impedance voltmeter. When
using the internal 1.5V or 1.6V references no external de-coupling capacitor must be
connected to AREF. High capacitive loading will de-stabilize the internal voltage
amplifier. The 1.6V reference voltage is calibrated to an absolute accuracy of 1 LSB
during the manufacturing process.
If the user has a fixed voltage source connected to the AREF pin, the user may not use
the other reference voltage options in the application, as they will be shorted to the
external voltage. An external reference voltage must be supplied with a very low
impedance R
(see
dependent and changes (current steps) in the course of the successive approximation
process. If no external voltage is applied to the AREF pin, the user may switch between
AVDD, 1.5V and 1.6V as reference selection.
Changes of the reference selection bits REFSn will only take effect until the first
conversion start is requested by setting ADSC in ADCSRA. After this the ADC has to be
disabled and enabled again for new reference selections. For internal references a
stable voltage is indicated by the REFOK bit in ADCSRB.
The ADC features a noise canceller that enables conversion during sleep mode to
reduce noise induced from the CPU core and other I/O peripherals. The noise canceller
can be used with ADC Noise Reduction and Idle mode. To make use of this feature, the
following procedure should be used:
1. Make sure that the ADC is enabled and is not busy converting. Single Conversion
2. Enter ADC Noise Reduction mode (or Idle mode). The ADC will start a conversion
A D C C lo ck
M U X 5 :0
M U X 5 :0
A D IF
A D C H
A D C L
mode must be selected and the ADC Conversion Complete interrupt must be
enabled.
once the CPU has been halted.
"ADC Characteristics" on page
in te rn a l
O ld C h a n n e l
AREF,EXT
C o n ve rsio n
1 1 T
C o n ve rsio n
C o m p le te
A D C _ C L K
(see
O ld C h a n n e l
N e w C h a n n e l
"ADC Characteristics" on page
t
C H D L Y
REF
REF
S ig n a n d M S B o f R e su lt
L S B o f R e su lt
509) seen by the external source is code
) indicates the conversion range for the ADC.
A D C S e ttlin g
N e w C h a n n e l
will result 0x3FF. V
t
A S E T
A D C In p u t
C h a n n e l is
ch a n g e d
509). The load current I
REF
N e w C o n ve rsio n
ca n b e sta rte d
fro m h e re
can be selected by the
8266B-MCU Wireless-03/11
L,AREF