ATSAM3X4EA-AU Atmel, ATSAM3X4EA-AU Datasheet - Page 788

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ATSAM3X4EA-AU

Manufacturer Part Number
ATSAM3X4EA-AU
Description
ARM Microcontrollers - MCU QFP144,GREEN, IND TEMP, MRL A
Manufacturer
Atmel
Datasheet

Specifications of ATSAM3X4EA-AU

Rohs
yes
Core
ARM Cortex M3
Processor Series
SAM3X
Data Bus Width
32 bit
Maximum Clock Frequency
84 MHz
Program Memory Size
256 KB
Data Ram Size
64 KB
On-chip Adc
Yes
Operating Supply Voltage
2.4 V to 3.6 V
Operating Temperature Range
- 40 C to +85 C
Package / Case
LQFP-144
Mounting Style
SMD/SMT
Factory Pack Quantity
60

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
ATSAM3X4EA-AU
Manufacturer:
Atmel
Quantity:
10 000
36.7.2
788
788
SAM3X/A
SAM3X/A
Receiver and Transmitter Control
Rate Generator Register (US_BRGR). The resulting clock can be provided to the SCK pin to
feed the smart card clock inputs. This means that the CLKO bit can be set in US_MR.
This clock is then divided by the value programmed in the FI_DI_RATIO field in the FI_DI_Ratio
register (US_FIDI). This is performed by the Sampling Divider, which performs a division by up
to 2047 in ISO7816 Mode. The non-integer values of the Fi/Di Ratio are not supported and the
user must program the FI_DI_RATIO field to a value as close as possible to the expected value.
The FI_DI_RATIO field resets to the value 0x174 (372 in decimal) and is the most common
divider between the ISO7816 clock and the bit rate (Fi = 372, Di = 1).
Figure 36-5
and the ISO 7816 clock.
Figure 36-5. Elementary Time Unit (ETU)
After reset, the receiver is disabled. The user must enable the receiver by setting the RXEN bit
in the Control Register (US_CR). However, the receiver registers can be programmed before the
receiver clock is enabled.
After reset, the transmitter is disabled. The user must enable it by setting the TXEN bit in the
Control Register (US_CR). However, the transmitter registers can be programmed before being
enabled.
The Receiver and the Transmitter can be enabled together or independently.
At any time, the software can perform a reset on the receiver or the transmitter of the USART by
setting the corresponding bit, RSTRX and RSTTX respectively, in the Control Register
(US_CR). The software resets clear the status flag and reset internal state machines but the
user interface configuration registers hold the value configured prior to software reset. Regard-
less of what the receiver or the transmitter is performing, the communication is immediately
stopped.
The user can also independently disable the receiver or the transmitter by setting RXDIS and
TXDIS respectively in US_CR. If the receiver is disabled during a character reception, the
USART waits until the end of reception of the current character, then the reception is stopped. If
the transmitter is disabled while it is operating, the USART waits the end of transmission of both
the current character and character being stored in the Transmit Holding Register (US_THR). If
a timeguard is programmed, it is handled normally.
ISO7816 I/O Line
ISO7816 Clock
shows the relation between the Elementary Time Unit, corresponding to a bit time,
on SCK
on TXD
ISO7816 Clock Cycles
FI_DI_RATIO
1 ETU
11057B–ATARM–28-May-12
11057B–ATARM–28-May-12

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