AT91SAM7S256C-MU Atmel, AT91SAM7S256C-MU Datasheet - Page 293

• Manufacturer Part Number: AT91SAM7S256C-MU
• Description: IC ARM7 MCU 32BIT 256K 64-QFN
• Manufacturer: Atmel
• Series: AT91SAMr

Specifications of AT91SAM7S256C-MU

• Core Processor: ARM7
• Core Size: 16/32-Bit
• Speed: 55MHz
• Connectivity: I²C, SPI, SSC, UART/USART, USB
• Peripherals: Brown-out Detect/Reset, DMA, POR, PWM, WDT
• Number Of I /o: 32
• Program Memory Size: 256KB (256K x 8)
• Program Memory Type: FLASH
• Ram Size: 64K x 8
• Voltage - Supply (vcc/vdd): 1.65 V ~ 1.95 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-VQFN Exposed Pad, 64-HVQFN, 64-SQFN, 64-DHVQFN
• Processor Series: AT91
• Core: ARM7TDMI
• Data Bus Width: 32 bit
• Data Ram Size: 64 KB
• Interface Type: SPI, TWI, USART, USB
• Maximum Clock Frequency: 55 MHz
• Number Of Programmable I/os: 32
• Number Of Timers: 5
• Operating Supply Voltage: 3.3 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Operating Temperature Range: - 40 C to + 85 C
• For Use With: AT91SAM-ICE - EMULATOR FOR AT91 ARM7/ARM9AT91SAM7S-EK - KIT EVAL FOR ARM AT91SAM7S
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details
• Other names: AT91SAM7S256-MU; AT91SAM7S256-MU

29.5.2
29.5.3
29.6
29.6.1
6175K–ATARM–30-Aug-10
Functional Description
Power Management
Interrupt
Transfer format
high. The output stages of devices connected to the bus must have an open-drain or open-col-
lector to perform the wired-AND function.
TWD and TWCK pins may be multiplexed with PIO lines. To enable the TWI, the programmer
must perform the following 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.
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
29-4 on page
Each transfer begins with a START condition and terminates with a STOP condition (see
29-3 on page
Figure 29-3.
Figure 29-4. Transfer Format
• 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.
– Dedicate TWD and TWCK as peripheral lines.
– Define TWD and TWCK as open-drain.
TWCK
TWD
293).
293).
START and STOP Conditions
Start Address R/W
TWCK
TWD
Start
AT91SAM7S Series Preliminary
Ack
Data
Ack
Data
Stop
Ack
Stop
Figure
Figure
293