SAM7XC256 Atmel Corporation, SAM7XC256 Datasheet - Page 51

• Manufacturer Part Number: SAM7XC256
• Manufacturer: Atmel Corporation

Specifications of SAM7XC256

• Flash (kbytes): 256 Kbytes
• Pin Count: 100
• Max. Operating Frequency: 55 MHz
• Cpu: ARM7TDMI
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 62
• Ext Interrupts: 62
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 2
• Twi (i2c): 1
• Uart: 3
• Can: 1
• Ssc: 1
• Ethernet: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 384
• Resistive Touch Screen: No
• Dac Resolution (bits): No
• Temp. Sensor: No
• Crypto Engine: AES/DES
• Sram (kbytes): 64
• Self Program Memory: NO
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 3.3
• Operating Voltage (vcc): 3.0 to 3.6
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 3
• Output Compare Channels: 3
• Input Capture Channels: 3
• Pwm Channels: 4
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: No

2.3.2
ARM DDI 0029G
31
Big-Endian
Byte at address A
Halfword at address A
In big-endian format, the ARM7TDMI processor stores the most significant byte of a
word at the lowest-numbered byte, and the least significant byte at the
highest-numbered byte. So the byte at address 0 of the memory system connects to data
lines 31 through 24.
For a word-aligned address A, Figure 2-2 shows how the word at address A, the
halfword at addresses A and A+2, and the bytes at addresses A, A+1, A+2, and A+3
map on to each other when the core is configured as big-endian.
24 23
Byte at address A+1
Copyright © 1994-2001. All rights reserved.
Figure 2-2 Big-endian addresses of bytes and halfwords within words
Word at address A
16 15
Byte at address A+2
Halfword at address A+2
8 7
Byte at address A+3
Programmer’s Model
0
2-5