AT91SAM7A1-AU Atmel, AT91SAM7A1-AU Datasheet - Page 28

• 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: -

10.3
10.3.1
10.3.2
10.3.3
10.3.3.1
28
External Memory Device Connection
AT91SAM7A1
Data Bus Width
Byte Select or Byte Write Access
Byte Select Access (BAT = 1)
16-bit Access Device Connection
Each chip select can access 8- or 16-bit data bus devices. This option is selected by the
DBW[1:0] bits in the corresponding AMC_CSRx register.
NCS0 is used at reset to access a 16-bit memory device (DBW[1:0] = 01
Each chip select can operate with one of two different types of write access by setting the Byte
Access Type (BAT) bit in the corresponding AMC_CSRx register.
This mode is selected by setting the bit BAT to 1 in AMC_CSRx registers and is typically used
to connect 16-bit devices in a memory page, except when user wants to connect 2 x 8-bit
devices in parallel, in that case seen by the AMC this is a 16-bit memory page.
Users can use the upper/lower bank selection signals NUB and NLB to have either an 8-bit or
a 16-bit access.
A typical 16-bit memory (e.g., Flash memory) device connection with 16-bit access is shown in
Figure
Figure 10-1. EBI Connection for External 16-bit Memory Device, 16-bit Access Only
• Byte select access (BAT = 1): Uses one write signal, one read signal, and two signals to
• Byte write access (BAT = 0): Uses two byte write signals to select two different 8-bit devices
• The signal A0/NLB is not used
• The signal NWR1/NUB is not used
• The signal NWR0/NWE is used as NWE and enables half-word writes.
• The signal NRD/NOE is used as NOE and enables half-word reads.
select upper and/or lower memory bank in a 16-bit memory.
Typically used with 16-bit memories, except when the user wants to connect 2 x 8-bit mem-
ories in parallel. In this case, this is considered a 16-bit memory by the AMC.
and a single read signal. This mode is used at reset to boot on the memory connected on
NCS0 (Chip Select 0).
Typically used with 2 x 8-bit memories.
10-1.
EBI
D[15:0]
A[21:1]
NWE
NOE
NCS
External Memory
D[15:0]
A[20:0]
NWE
NOE
NCE
16-bit
b
).
6048B–ATARM–29-Jun-06