AT91SAM7A1-AU Atmel, AT91SAM7A1-AU Datasheet - Page 32

• Manufacturer Part Number: AT91SAM7A1-AU
• Description: IC ARM7 MCU 32BIT ROMLESS144LQFP
• Manufacturer: Atmel
• Series: AT91SAMr

Specifications of AT91SAM7A1-AU

• Core Processor: ARM7
• Core Size: 16/32-Bit
• Speed: 40MHz
• Connectivity: CAN, EBI/EMI, SPI, UART/USART
• Peripherals: POR, PWM, WDT
• Number Of I /o: 49
• Program Memory Type: ROMless
• Ram Size: 4K x 8
• Voltage - Supply (vcc/vdd): 3 V ~ 3.6 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 144-LQFP
• For Use With: AT91SAM7A1-EK - BOARD EVAL FOR AT91SAM7A1
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Program Memory Size: -

10.4
10.4.1
10.4.1.1
32
External Bus Interface Timings
AT91SAM7A1
Read Access
Standard Read Protocol
Figure 10-6. EBI Connection for External 16-bit Memory Devices, 16-bit Access Only
If users want to boot on a RAM memory for debug purposes, the RAM memory should be con-
nected the same way as a Flash memory (NUB and NLB of the RAM memory connected to
the ground) to emulate a pure 16-bit Flash memory as shown in
Figure 10-7. EBI Connected to an External 16-bit RAM Memory Device, 16-bit Access Only
Simple read and write access cycles are explained in detail where read access can be done
through two modes:
The EBI can automatically insert wait states during the external access cycles. These wait
states are applied within the actual access cycle.
Data float wait states can also be inserted and applied between cycles. Data float wait states
depend on the previous access.
Standard read protocol (default read mode) implements a read cycle in which NRD/NOE is
active during the second half of the read cycle.
The first half of the read cycle allows time to ensure completion of the previous access, as well
as the output of address and NCS before the read cycle begins.
• Standard read protocol
• Early read protocol which increases the EBI performance for read access.
Used as a Boot Memory for Debug Purpose
EBI
EBI
D[15:0]
A[21:1]
D[15:0]
A[21:1]
NWR0
NWR0
NRD
NCS
NRD
NCS
External Memory
External Memory
D[15:0]
A[20:0]
NWE
NOE
NCE
NLB
NUB
D[15:0]
A[20:0]
NWE
NOE
NCE
16-bit RAM
16-bit
Figure
10-7.
6048B–ATARM–29-Jun-06