A000047 Arduino, A000047 Datasheet - Page 38

• Manufacturer Part Number: A000047
• Description: MCU, MPU & DSP Development Tools Mega2560
• Manufacturer: Arduino
• Series: -r
• Type: MCUr

Specifications of A000047

• Processor To Be Evaluated: ATmega2560
• Interface Type: USB, I2C, SPI
• Dimensions: 4 in x 2.1 in
• Operating Supply Voltage: 5 V
• Contents: Board
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: ATmega2560

8.4.2
2549M–AVR–09/10
XMCRB – External Memory Control Register B
Figure 8-1 on page
external memory address space is treated as one sector. When the entire SRAM address space
is configured as one sector, the wait-states are configured by the SRW11 and SRW10 bits.
Table 8-2.
• Bit 3:2 – SRW11, SRW10: Wait-state Select Bits for Upper Sector
The SRW11 and SRW10 bits control the number of wait-states for the upper sector of the exter-
nal memory address space, see
• Bit 1:0 – SRW01, SRW00: Wait-state Select Bits for Lower Sector
The SRW01 and SRW00 bits control the number of wait-states for the lower sector of the exter-
nal memory address space, see
Table 8-3.
Note:
Bit
(0x75)
Read/Write
Initial Value
SRWn1
SRL2
0
0
1
1
0
0
0
1
1
1
1
1. n = 0 or 1 (lower/upper sector).
For further details of the timing and wait-states of the External Memory Interface, see Figures
8-3 through Figures 8-6 for how the setting of the SRW bits affects the timing.
SRWn0
XMBK
Sector limits with different settings of SRL2:0
Wait States
R/W
0
1
0
1
7
0
SRL1
28. By default, the SRL2, SRL1, and SRL0 bits are set to zero and the entire
0
1
1
0
0
1
1
Wait two cycles during read/write and wait one cycle before driving out new
R
6
–
0
(1)
SRL0
ATmega640/1280/1281/2560/2561
Table
Table
x
0
1
0
1
0
1
R
5
–
0
8-3.
8-3.
Wait two cycles during read/write strobe
Wait one cycle during read/write strobe
R
4
–
0
No wait-states
R
3
–
0
Wait States
Upper sector = 0xA000 - 0xFFFF
Upper sector = 0xC000 - 0xFFFF
Upper sector = 0xE000 - 0xFFFF
Upper sector = 0x2200 - 0xFFFF
Upper sector = 0x4000 - 0xFFFF
Upper sector = 0x6000 - 0xFFFF
Upper sector = 0x8000 - 0xFFFF
Lower sector = 0x2200 - 0xBFFF
Lower sector = 0x2200 - 0xDFFF
Lower sector = 0x2200 - 0x3FFF
Lower sector = 0x2200 - 0x5FFF
Lower sector = 0x2200 - 0x7FFF
Lower sector = 0x2200 - 0x9FFF
address
Lower sector = N/A
XMM2
R/W
Sector Limits
2
0
XMM1
R/W
1
0
XMM0
R/W
0
0
XMCRB
38