AT91SAM7X256B-AU Atmel, AT91SAM7X256B-AU Datasheet - Page 355

• Manufacturer Part Number: AT91SAM7X256B-AU
• Description: IC MCU 256KB FLASH 100LQFP
• Manufacturer: Atmel
• Series: AT91SAMr

Specifications of AT91SAM7X256B-AU

• Core Processor: ARM7
• Core Size: 16/32-Bit
• Speed: 55MHz
• Connectivity: CAN, Ethernet, I²C, SPI, SSC, UART/USART, USB
• Peripherals: Brown-out Detect/Reset, DMA, POR, PWM, WDT
• Number Of I /o: 62
• 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: 100-LQFP
• Package: 100LQFP
• Device Core: ARM7TDMI
• Family Name: 91S
• Maximum Speed: 55 MHz
• Operating Supply Voltage: 1.8|3.3 V
• Data Bus Width: 32 Bit
• Number Of Programmable I/os: 62
• Interface Type: CAN/Ethernet/SPI/I2S/TWI/USART/USB
• On-chip Adc: 8-chx10-bit
• Number Of Timers: 3
• Controller Family/series: AT91SAM7xxxxx
• No. Of I/o's: 62
• Ram Memory Size: 64KB
• Cpu Speed: 55MHz
• No. Of Timers: 1
• Rohs Compliant: Yes
• Cpu Family: 91S
• Device Core Size: 32b
• Frequency (max): 55MHz
• Total Internal Ram Size: 64KB
• # I/os (max): 62
• Number Of Timers - General Purpose: 3
• Operating Supply Voltage (typ): 1.8/3.3V
• Operating Supply Voltage (max): 1.95/3.6V
• Operating Supply Voltage (min): 1.65/3V
• Instruction Set Architecture: RISC
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 100
• Package Type: LQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Compliant

31.6.1.1
Figure 31-4. Divided Clock Block Diagram
Figure 31-5.
31.6.1.2
6120H–ATARM–17-Feb-09
Clock Divider
Transmitter Clock Management
Divided Clock Generation
The Master Clock divider is determined by the 12-bit field DIV counter and comparator (so its
maximal value is 4095) in the Clock Mode Register SSC_CMR, allowing a Master Clock division
by up to 8190. The Divided Clock is provided to both the Receiver and Transmitter. When this
field is programmed to 0, the Clock Divider is not used and remains inactive.
When DIV is set to a value equal to or greater than 1, the Divided Clock has a frequency of Mas-
ter Clock divided by 2 times DIV. Each level of the Divided Clock has a duration of the Master
Clock multiplied by DIV. This ensures a 50% duty cycle for the Divided Clock regardless of
whether the DIV value is even or odd.
Table 31-2.
The transmitter clock is generated from the receiver clock or the divider clock or an external
clock scanned on the TK I/O pad. The transmitter clock is selected by the CKS field in
SSC_TCMR (Transmit Clock Mode Register). Transmit Clock can be inverted independently by
the CKI bits in SSC_TCMR.
The transmitter can also drive the TK I/O pad continuously or be limited to the actual data trans-
fer. The clock output is configured by the SSC_TCMR register. The Transmit Clock Inversion
(CKI) bits have no effect on the clock outputs. Programming the TCMR register to select TK pin
Maximum
MCK / 2
Divided Clock
Divided Clock
Master Clock
Master Clock
DIV = 3
DIV = 1
MCK
/ 2
Divided Clock Frequency = MCK/2
Divided Clock Frequency = MCK/6
AT91SAM7X512/256/128 Preliminary
Clock Divider
12-bit Counter
SSC_CMR
Minimum
MCK / 8190
Divided Clock
355