M55800A Atmel Corporation, M55800A Datasheet - Page 24

• Manufacturer Part Number: M55800A
• Manufacturer: Atmel Corporation

Specifications of M55800A

• Flash (kbytes): 0 Kbytes
• Pin Count: 176
• Max. Operating Frequency: 33 MHz
• Cpu: ARM7TDMI
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 58
• Ext Interrupts: 58
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Uart: 3
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 72
• Resistive Touch Screen: No
• Dac Channels: 1
• Dac Resolution (bits): 10
• 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

Byte Write or Byte Select
Access
24
AT91X40 Series
Each chip select with a 16-bit data bus can operate with one of two different types of
write access:
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•
This option is controlled by the BAT field in the EBI_CSR (Chip Select Register) for the
corresponding chip select.
Byte Write Access is used to connect 2 x 8-bit devices as a 16-bit memory page.
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•
•
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Figure 11 shows how to connect two 512K x 8-bit devices in parallel on NCS2.
Figure 11. Memory Connection for 2 x 8-bit Data Busses
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 read and write signals.
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.
EBI
D8 - D15
A1 - A19
D0 - D7
NWR1
NWR0
NCS2
NRD
A0
D0 - D7
A0 - A18
Write Enable
Read Enable
Memory Enable
D8 - D15
A0 - A18
Write Enable
Read Enable
Memory Enable
1354D–ATARM–08/02