ATMEGA2560R231-AU Atmel, ATMEGA2560R231-AU Datasheet - Page 37

• Manufacturer Part Number: ATMEGA2560R231-AU
• Description: BUNDLE ATMEGA2560/RF231 TQFP
• Manufacturer: Atmel

Specifications of ATMEGA2560R231-AU

• Frequency: 2.4GHz
• Modulation Or Protocol: 802.15.4 Zigbee, 6LoWPAN, RF4CE, SP100, WirelessHART™, ISM
• Data Interface: PCB, Surface Mount
• Memory Size: 256kB Flash, 4kB EEPROM, 8kB RAM
• Antenna Connector: PCB, Surface Mount
• Package / Case: 100-TFBGA
• Processor Series: ATMEGA256x
• Core: AVR8
• Data Bus Width: 8 bit
• Program Memory Type: Flash
• Program Memory Size: 256 KB
• Data Ram Size: 8 KB
• Development Tools By Supplier: ATAVRRZ541, ATAVRRAVEN, ATAVRRZRAVEN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Supply: -
• Power - Output: -
• Operating Temperature: -
• Applications: -
• Sensitivity: -
• Data Rate - Maximum: -
• Current - Transmitting: -
• Current - Receiving: -
• Lead Free Status / Rohs Status: Details

8.3
8.3.1
8.3.2
8.3.3
8.4
8.4.1
2549M–AVR–09/10
General Purpose registers
External Memory registers
GPIOR2 – General Purpose I/O Register 2
GPIOR1 – General Purpose I/O Register 1
GPIOR0 – General Purpose I/O Register 0
XMCRA – External Memory Control Register A
• Bit 0 – EERE: EEPROM Read Enable
The EEPROM Read Enable Signal EERE is the read strobe to the EEPROM. When the correct
address is set up in the EEAR Register, the EERE bit must be written to a logic one to trigger the
EEPROM read. The EEPROM read access takes one instruction, and the requested data is
available immediately. When the EEPROM is read, the CPU is halted for four cycles before the
next instruction is executed.
The user should poll the EEPE bit before starting the read operation. If a write operation is in
progress, it is neither possible to read the EEPROM, nor to change the EEAR Register.
• Bit 7 – SRE: External SRAM/XMEM Enable
Writing SRE to one enables the External Memory Interface.The pin functions AD7:0, A15:8,
ALE, WR, and RD are activated as the alternate pin functions. The SRE bit overrides any pin
direction settings in the respective data direction registers. Writing SRE to zero, disables the
External Memory Interface and the normal pin and data direction settings are used.
• Bit 6:4 – SRL2:0: Wait-state Sector Limit
It is possible to configure different wait-states for different External Memory addresses. The
external memory address space can be divided in two sectors that have separate wait-state bits.
The SRL2, SRL1, and SRL0 bits select the split of the sectors, see
Bit
0x2B (0x4B)
Read/Write
Initial Value
Bit
0x2A (0x4A)
Read/Write
Initial Value
Bit
0x1E (0x3E)
Read/Write
Initial Value
Bit
“(0x74)”
Read/Write
Initial Value
MSB
MSB
MSB
R/W
R/W
R/W
SRE
R/W
7
0
7
0
7
0
7
0
SRL2
R/W
R/W
R/W
R/W
6
0
6
0
6
0
6
0
ATmega640/1280/1281/2560/2561
SRL1
R/W
R/W
R/W
R/W
5
0
5
0
5
0
5
0
SRL0
R/W
R/W
R/W
R/W
4
0
4
0
4
0
4
0
SRW11
R/W
R/W
R/W
R/W
3
0
3
0
3
0
3
0
SRW10
R/W
R/W
R/W
R/W
2
0
2
0
2
0
2
0
Table 8-2 on page 38
SRW01
R/W
R/W
R/W
R/W
1
0
1
0
1
0
1
0
SRW00
LSB
LSB
LSB
R/W
R/W
R/W
R/W
0
0
0
0
0
0
0
0
GPIOR2
GPIOR1
GPIOR0
XMCRA
and
37