ATMEGA2560R231-AU Atmel, ATMEGA2560R231-AU Datasheet - Page 170

BUNDLE ATMEGA2560/RF231 TQFP

ATMEGA2560R231-AU

Manufacturer Part Number
ATMEGA2560R231-AU
Description
BUNDLE ATMEGA2560/RF231 TQFP
Manufacturer
Atmel
Datasheet

Specifications of ATMEGA2560R231-AU

Frequency
2.4GHz
Modulation Or Protocol
802.15.4 Zigbee, 6LoWPAN, RF4CE, SP100, WirelessHART™, ISM
Data Interface
PCB, Surface Mount
Memory Size
256kB Flash, 4kB EEPROM, 8kB RAM
Antenna Connector
PCB, Surface Mount
Package / Case
100-TFBGA
Processor Series
ATMEGA256x
Core
AVR8
Data Bus Width
8 bit
Program Memory Type
Flash
Program Memory Size
256 KB
Data Ram Size
8 KB
Development Tools By Supplier
ATAVRRZ541, ATAVRRAVEN, ATAVRRZRAVEN
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Voltage - Supply
-
Power - Output
-
Operating Temperature
-
Applications
-
Sensitivity
-
Data Rate - Maximum
-
Current - Transmitting
-
Current - Receiving
-
Lead Free Status / Rohs Status
 Details
17.4
17.4.1
2549M–AVR–09/10
Register Description
GTCCR – General Timer/Counter Control Register
The synchronization and edge detector logic introduces a delay of 2.5 to 3.5 system clock cycles
from an edge has been applied to the Tn pin to the counter is updated.
Enabling and disabling of the clock input must be done when Tn has been stable for at least one
system clock cycle, otherwise it is a risk that a false Timer/Counter clock pulse is generated.
Each half period of the external clock applied must be longer than one system clock cycle to
ensure correct sampling. The external clock must be guaranteed to have less than half the sys-
tem clock frequency (f
sampling, the maximum frequency of an external clock it can detect is half the sampling fre-
quency (Nyquist sampling theorem). However, due to variation of the system clock frequency
and duty cycle caused by Oscillator source (crystal, resonator, and capacitors) tolerances, it is
recommended that maximum frequency of an external clock source is less than f
An external clock source can not be prescaled.
Figure 17-2. Prescaler for synchronous Timer/Counters
Bit
0x23 (0x43)
Read/Write
Initial Value
• Bit 7 – TSM: Timer/Counter Synchronization Mode
Writing the TSM bit to one activates the Timer/Counter Synchronization mode. In this mode, the
value that is written to the PSRASY and PSRSYNC bits is kept, hence keeping the correspond-
ing prescaler reset signals asserted. This ensures that the corresponding Timer/Counters are
halted and can be configured to the same value without the risk of one of them advancing during
configuration. When the TSM bit is written to zero, the PSRASY and PSRSYNC bits are cleared
by hardware, and the Timer/Counters start counting simultaneously.
PSR10
clk
CSn0
CSn1
CSn2
Tn
Tn
I/O
Synchronization
Synchronization
TSM
R/W
7
0
ExtClk
R
6
0
< f
TIMER/COUNTERn CLOCK SOURCE
clk_I/O
ATmega640/1280/1281/2560/2561
/2) given a 50/50% duty cycle. Since the edge detector uses
R
5
0
clk
Clear
Tn
R
4
0
R
3
0
CSn0
CSn1
CSn2
R
2
0
TIMER/COUNTERn CLOCK SOURCE
PSRASY PSRSYNC
R/W
1
0
clk
Tn
R/W
clk_I/O
0
0
/2.5.
GTCCR
170

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