M42800A Atmel Corporation, M42800A Datasheet - Page 96

• Manufacturer Part Number: M42800A
• Manufacturer: Atmel Corporation

Specifications of M42800A

• Flash (kbytes): 0 Kbytes
• Pin Count: 144
• Max. Operating Frequency: 33 MHz
• Cpu: ARM7TDMI
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 54
• Ext Interrupts: 54
• Usb Speed: No
• Usb Interface: No
• Spi: 2
• Uart: 2
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 8
• Self Program Memory: NO
• External Bus Interface: 1
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 3.3/5.0
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 6
• Output Compare Channels: 6
• Input Capture Channels: 6
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: No

Memory Interface
3.6.4
3-26
Byte and halfword accesses
nMREQ
D[15:8]
A[31:0]
BL[3:0]
nWAIT
MCLK
D[7:0]
SEQ
APE
The processor indicates the size of a transfer by use of the MAS[1:0] signal as described
in MAS[1:0] on page 3-11.
Byte, halfword, and word accesses are described in:
•
•
Reads
When a halfword or byte read is performed, a 32-bit memory system can return the
complete 32-bit word, and the processor extracts the valid halfword or byte field from
it. The fields extracted depend on the state of the BIGEND signal, which determines
the endian configuration of the system. See Memory formats on page 2-4.
A word read from 32-bit memory presents the word value on the whole data bus as listed
in Table 3-7.
When connecting 8-bit to 16-bit memory systems to the processor, ensure that the data
is presented to the correct byte lanes on the core as listed in Table 3-7 on page 3-27.
Reads on page 3-26
Writes on page 3-27.
Copyright © 1994-2001. All rights reserved.
0xF
Figure 3-19 Two cycle memory access
0x2
ARM DDI 0029G