SAM7X128 Atmel Corporation, SAM7X128 Datasheet - Page 81

• Manufacturer Part Number: SAM7X128
• Manufacturer: Atmel Corporation

Specifications of SAM7X128

• Flash (kbytes): 128 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
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 32
• 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

3.4
3.4.1
3.4.2
3.4.3
ARM DDI 0029G
Addressing signals
A[31:0]
nRW
MAS[1:0]
The address class signals are:
•
•
•
•
•
•
•
A[31:0] is the 32-bit address bus that specifies the address for the transfer. All addresses
are byte addresses, so a burst of word accesses results in the address bus incrementing
by four for each cycle.
The address bus provides 4GB of linear addressing space.
When a word access is signaled the memory system ignores the bottom two bits, A[1:0],
and when a halfword access is signaled the memory system ignores the bottom bit,
A[0].
All data values must be aligned on their natural boundaries. All words must be
word-aligned.
nRW specifies the direction of the transfer. nRW indicates an ARM7TDMI processor
write cycle when HIGH, and an ARM7TDMI processor read cycle when LOW. A burst
of S-cycles is always either a read burst, or a write burst. The direction cannot be
changed in the middle of a burst.
The MAS[1:0] bus encodes the size of the transfer. The ARM7TDMI processor can
transfer word, halfword, and byte quantities.
All writable memory in an ARM7TDMI processor based system must support the
writing of individual bytes or halfwords to allow the use of the C Compiler and the
ARM debug tool chain, for example Multi-ICE.
A[31:0] on page 3-11
nRW on page 3-11
MAS[1:0] on page 3-11
nOPC on page 3-12
nTRANS on page 3-13
LOCK on page 3-13
TBIT on page 3-13.
Copyright © 1994-2001. All rights reserved.
Memory Interface
3-11