M42800A Atmel Corporation, M42800A Datasheet - Page 27

• 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

11.7
1779D–ATARM–14-Apr-06
Byte Write or Byte Select Access
Figure 11-4. Memory Connection for an 8-bit Data Bus
Figure 11-5 shows how to connect a 512K x 16-bit memory on NCS2.
Figure 11-5. Memory Connection for a 16-bit Data Bus
Each chip select with a 16-bit data bus can operate with one of two different types of write
access:
This option is controlled by the BAT field in the EBI_CSR (Chip Select Register) for the corre-
sponding chip select.
Byte Write Access is used to connect 2 x 8-bit devices as a 16-bit memory page.
Figure 11-6 shows how to connect two 512K x 8-bit devices in parallel on NCS2.
• Byte Write Access supports two byte write and a single read signal.
• Byte Select Access selects upper and/or lower byte with two byte select lines, and separate
• The signal A0/NLB is not used.
• The signal NWR1/NUB is used as NWR1 and enables upper byte writes.
• The signal NWR0/NWE is used as NWR0 and enables lower byte writes.
• The signal NRD/NOE is used as NRD and enables half-word and byte reads.
read and write signals.
EBI
EBI
D8 - D15
A1 - A19
D8 - D15
A1 - A18
D0 - D7
D0 - D7
NWR1
NWR0
NCS2
NCS2
NWE
NOE
NUB
NRD
NLB
A0
D0 - D7
D8 - D15
A0 - A18
Low Byte Enable
High Byte Enable
Write Enable
Output Enable
Memory Enable
D0 - D7
A1 - A18
A0
Write Enable
Output Enable
Memory Enable
AT91M42800A
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