AT91SAM7X128 Atmel, AT91SAM7X128 Datasheet - Page 94

• Manufacturer Part Number: AT91SAM7X128
• Description: MCU 32-Bit 91S ARM7TDMI RISC 128KB Flash 1.8V/3.3V 100-Pin LQFP
• Manufacturer: Atmel

Specifications of AT91SAM7X128

• Package: 100LQFP
• Device Core: ARM7TDMI
• Family Name: 91S
• Maximum Speed: 55 MHz
• Ram Size: 32 KB
• Program Memory Size: 128 KB
• Operating Supply Voltage: 1.8|3.3 V
• Data Bus Width: 32 Bit
• Program Memory Type: Flash
• Number Of Programmable I/os: 62
• Interface Type: CAN/Ethernet/SPI/I2S/TWI/USART/USB
• On-chip Adc: 8-chx10-bit
• Operating Temperature: -40 to 85 °C
• Number Of Timers: 3

18.3
18.3.1
18.3.2
94
Functional Description
AT91SAM7X512/256/128 Preliminary
Bus Arbiter
Address Decoder
The Memory Controller handles the internal ASB bus and arbitrates the accesses of up to three
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 three masters. The EMAC has the highest priority; the Peripheral DMA Control-
ler has the medium 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
0x0000 0000
0xF000 0000
0x0FFF FFFF
0xEFFF FFFF
0xFFFF FFFF
0x1000 0000
Internal Memories
Peripherals
Undefined
(Abort)
6120H–ATARM–17-Feb-09