AT91M40800-33AI Atmel, AT91M40800-33AI Datasheet - Page 28

• Manufacturer Part Number: AT91M40800-33AI
• Description: IC ARM7 MCU 100 TQFP
• Manufacturer: Atmel
• Series: AT91SAMr

Specifications of AT91M40800-33AI

• Core Processor: ARM7
• Core Size: 16/32-Bit
• Speed: 33MHz
• Connectivity: EBI/EMI, UART/USART
• Peripherals: POR, WDT
• Number Of I /o: 32
• Program Memory Type: ROMless
• Ram Size: 8K x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 3.6 V
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 100-LQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Program Memory Size: -
• Data Converters: -

Write Data Hold Time
28
AT91X40 Series
Figure 15. Early Read Protocol
Figure 16. Early Read Wait State
During write cycles in both protocols, output data becomes valid after the falling edge of
the NWE signal and remains valid after the rising edge of NWE, as illustrated in Figure
17. The external NWE waveform (on the NWE pin) is used to control the output data tim-
ing to guarantee this operation.
It is therefore necessary to avoid excessive loading of the NWE pins, which could delay
the write signal too long and cause a contention with a subsequent read cycle in stan-
dard protocol.
ADDR
MCKI
NWE
NRD
NCS
or
ADDR
MCKI
NWE
NCS
NRD
Write Cycle
Early Read Wait
Read Cycle
1354D–ATARM–08/02