ATxmega32A4 Atmel Corporation, ATxmega32A4 Datasheet - Page 270

• Manufacturer Part Number: ATxmega32A4
• Manufacturer: Atmel Corporation

Specifications of ATxmega32A4

• Flash (kbytes): 32 Kbytes
• Pin Count: 44
• Max. Operating Frequency: 32 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 34
• Ext Interrupts: 34
• Usb Speed: No
• Usb Interface: No
• Spi: 7
• Twi (i2c): 2
• Uart: 5
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 12
• Adc Resolution (bits): 12
• Adc Speed (ksps): 2000
• Analog Comparators: 2
• Resistive Touch Screen: No
• Dac Channels: 2
• Dac Resolution (bits): 12
• Temp. Sensor: Yes
• Crypto Engine: AES/DES
• Sram (kbytes): 4
• Eeprom (bytes): 1024
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: Yes
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.6 to 3.6
• Operating Voltage (vcc): 1.6 to 3.6
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 5
• Output Compare Channels: 16
• Input Capture Channels: 16
• Pwm Channels: 16
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

24.5
24.6
24.6.1
24.6.2
8077H–AVR–12/09
EBI Clock
SRAM Configuration
No Multiplexing
Multiplexing address byte 0 and 1
The EBI is clocked from the Peripheral 2x (Clk
frequency, but it can also run at two times the CPU Clock frequency. This can be used to lower
the EBI access time. Refer to
Peripheral 2x Clock and how to configure this.
For use with SRAM the EBI can be configured for various address multiplexing modes by using
external address latches, or with no multiplexing. When a limited number of pins on the device
are is available for the EBI, Address Latch Enable (ALE) signals are used to control external
latches that multiplex address lines from the EBI. The available configurations is shown in
tion 24.6.1 on page 270
the SRAM interface signals.
Table 24-1.
When no multiplexing is used, there is a one-to-one connection between the EBI and the SRAM.
No external address latches are used.
Figure 24-2. Non-multiplexed SRAM connection
When address byte 0 (A[7:0]) and address byte 1 (A[15:8]) are multiplexed, they are output from
the same port, and the ALE1 signal from the device control the address latch.
Signal
CS
WE
RE
ALE[2:0]
A[23:0]
D[7:0]
AD[7:0]
SRAM Interface signals
EBI
Description
Chip Select
Write Enable
Read Enable
Address Latch Enable
Address
Data bus
Combined Address and Data
A[21:16]
through
A[15:8]
D[7:0]
A[7:0]
”System Clock and Clock options” on page 76
Section 24.6.4 on page
2PER
) Clock. This clock can run at the CPU Clock
271.
Table 24-1 on page 270
D[7:0]
A[7:0]
A[15:8]
A[21:16]
SRAM
XMEGA A
for details the
describe
Sec-
270