M55800A Atmel Corporation, M55800A Datasheet - Page 33

• 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

11.8
11.8.1
11.8.2
1745F–ATARM–06-Sep-07
Wait States
Standard Wait States
Data Float Wait State
The EBI can automatically insert wait states. The different types of wait states are listed below:
Each chip select can be programmed to insert one or more wait states during an access on the
corresponding device. This is done by setting the WSE field in the corresponding EBI_CSR. The
number of cycles to insert is programmed in the NWS field in the same register.
Below is the correspondence between the number of standard wait states programmed and the
number of cycles during which the NWE pulse is held low:
For each additional wait state programmed, an additional cycle is added.
Figure 11-11. One Wait State Access
Notes:
Some memory devices are slow to release the external bus. For such devices it is necessary to
add wait states (data float waits) after a read access before starting a write access or a read
access to a different external memory.
The Data Float Output Time (t
field of the EBI_CSR register for the corresponding chip select. The value (0 - 7 clock cycles)
indicates the number of data float waits to be inserted and represents the time allowed for the
data output to go high impedance after the memory is disabled.
• Standard wait states
• Data float wait states
• External wait states
• Chip select change wait states
• Early read wait states (as described in Read Protocols)
0 wait states
1 wait state
1. Early Read Protocol
2. Standard Read Protocol
ADDR
NWE
MCK
NRD
NCS
DF
(1)
) for each external memory device is programmed in the TDF
1 Wait State Access
1/2 cycle
1 cycle
(2)
AT91M5880A
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