M42800A Atmel Corporation, M42800A Datasheet - Page 25

• 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

11.4
Table 11-1.
Table 11-2.
11.5
1779D–ATARM–14-Apr-06
Name
A0 - A23
D0 - D15
NCS0 - NCS3
CS4 - CS7
NRD
NWR0 - NWR1
NOE
NWE
NUB, NLB
NWAIT
PME
A23 - A20
A0
NRD
NWR0
NWR1
Pin Description
Chip Select Lines
Multiplexed Signals
External Bus Interface Pin Description
EBI Multiplexed Signals
NLB
NOE
NWE
NUB
CS4 - CS7
The EBI provides up to eight chip select lines:
By exchanging address lines for chip select lines, the user can optimize the EBI to suit the
external memory requirements: more external devices or larger address range for each
device.
The selection is controlled by the ALE field in EBI_MCR (Memory Control Register). The fol-
lowing combinations are possible:
• Chip select lines NCS0 - NCS3 are dedicated to the EBI (not multiplexed).
• Chip select lines CS4 - CS7 are multiplexed with the top four address lines A23 - A20.
A20, A21, A22, A23 (configuration by default)
A20, A21, A22, CS4
A20, A21, CS5, CS4
A20, CS6, CS5, CS4
CS7, CS6, CS5, CS4
Description
Address bus
Data bus
Active low chip selects
Active high chip selects
Read Enable
Lower and upper write enable
Output enable
Write enable
Upper and lower byte select
Wait request
Protection Mode Enabled
Byte-write or byte select access
Functions
Allows from 4 to 8 chip select lines to be used
8- or 16-bit data bus
Byte-write or byte select access
Byte-write or byte select access
AT91M42800A
Output
Output
Output
Output
Output
Output
Output
Output
Type
Input
Input
I/O
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