AT91SAM7S256D-AU Atmel, AT91SAM7S256D-AU Datasheet - Page 321

• Manufacturer Part Number: AT91SAM7S256D-AU
• Description: ARM Microcontrollers - MCU 256K Flash SRAM 64K ARM based MCU
• Manufacturer: Atmel
• Series: SAM7S256r

Specifications of AT91SAM7S256D-AU

• Rohs: yes
• Core: ARM
• Processor Series: AT91SAM
• Data Bus Width: 16 bit/32 bit
• Maximum Clock Frequency: 55 MHz
• Program Memory Size: 256 KB
• Data Ram Size: 64 KB
• On-chip Adc: Yes
• Operating Supply Voltage: 3 V to 3.6 V
• Operating Temperature Range: - 40 C to + 85 C
• Package / Case: LQFP-64
• Mounting Style: SMD/SMT
• Interface Type: 2-Wire, I2S, SPI, USART
• Length: 7 mm

30.5.2
30.5.3
30.6
30.6.1
30.6.2
TWD and TWCK pins may be multiplexed with PIO lines. To enable the TWI, the programmer must perform the fol-
lowing steps:
The TWI interface may be clocked through the Power Management Controller (PMC), thus the programmer must
first configure the PMC to enable the TWI clock.
The TWI interface has an interrupt line connected to the Advanced Interrupt Controller (AIC). In order to handle
interrupts, the AIC must be programmed before configuring the TWI.
Functional Description
The data put on the TWD line must be 8 bits long. Data is transferred MSB first; each byte must be followed by an
acknowledgement. The number of bytes per transfer is unlimited (see
Each transfer begins with a START condition and terminates with a STOP condition (see
Figure 30-3.
Figure 30-4. Transfer Format
The TWI has six modes of operations:
• Program the PIO controller to:
• Enable the peripheral clock.
• A high-to-low transition on the TWD line while TWCK is high defines the START condition.
• A low-to-high transition on the TWD line while TWCK is high defines a STOP condition.
• Master transmitter mode
• Master receiver mode
• Multi-master transmitter mode
Power Management
Interrupt
Transfer Format
Modes of Operation
– Dedicate TWD and TWCK as peripheral lines.
– Define TWD and TWCK as open-drain.
START and STOP Conditions
TWD
TWCK
Start
Address
TWCK
TWD
R/W
Start
Ack
Data
Ack
Figure
Data
SAM7S Series [DATASHEET]
Stop
30-4).
Ack
Figure
6175M–ATARM–26-Oct-12
Stop
30-3).
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