AT91SAM7S256C-MU Atmel, AT91SAM7S256C-MU Datasheet - Page 98

• 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

18.3
18.3.1
18.3.2
98
Functional Description
AT91SAM7S Series Preliminary
Bus Arbiter
Address Decoder
The Memory Controller handles the internal ASB bus and arbitrates the accesses of both
masters.
It is made up of:
The MC handles only little-endian mode accesses. The masters work in little-endian mode only.
The Memory Controller has a simple, hard-wired priority bus arbiter that gives the control of the
bus to one of the two masters. The Peripheral DMA Controller has the highest priority; the ARM
processor has the lowest one.
The Memory Controller features an Address Decoder that first decodes the four highest bits of
the 32-bit address bus and defines three separate areas:
Figure 18-2
Figure 18-2. Memory Areas
• A bus arbiter
• An address decoder
• An abort status
• A misalignment detector
• An Embedded Flash Controller
• One 256-Mbyte address space for the internal memories
• One 256-Mbyte address space reserved for the embedded peripherals
• An undefined address space of 3584M bytes representing fourteen 256-Mbyte areas that
return an Abort if accessed
shows the assignment of the 256-Mbyte memory areas.
14 x 256MBytes
256M Bytes
256M Bytes
3,584 Mbytes
0xF000 0000
0x0000 0000
0xEFFF FFFF
0xFFFF FFFF
0x0FFF FFFF
0x1000 0000
Internal Memories
Peripherals
Undefined
(Abort)
6175K–ATARM–30-Aug-10