AT32UC3A464 Atmel Corporation, AT32UC3A464 Datasheet - Page 133

• Manufacturer Part Number: AT32UC3A464
• Manufacturer: Atmel Corporation

Specifications of AT32UC3A464

• Flash (kbytes): 64 Kbytes
• Pin Count: 100
• Max. Operating Frequency: 66 MHz
• Cpu: 32-bit AVR
• Hardware Qtouch Acquisition: No
• Usb Transceiver: 1
• Usb Speed: Hi-Speed
• Usb Interface: Device + OTG
• Spi: 6
• Twi (i2c): 2
• Uart: 4
• Ssc: 1
• Sd / Emmc: 2
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 128
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: Yes
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 3.0 to 3.6
• Operating Voltage (vcc): 3.0 to 3.6
• Fpu: No
• Timers: 6
• Output Compare Channels: 6
• Input Capture Channels: 6
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

12.4.7
12.5
32072G–11/2011
Flash commands
Writing words to a page that is not completely erased
When writing to the page buffer, the PAGEN field in the FCMD register is updated with the page
number corresponding to page address of the latest word written into the page buffer.
The page buffer is also used for writes to the User page.
Write operations can be prevented by programming the Memory Protection Unit of the CPU.
Writing 8-bit and 16-bit data to the page buffer is not allowed and may lead to unpredictable data
corruption.
Page buffer write operations are performed with 2.2.0 wait states.
Writing to the page buffer can only change page buffer bits from one to zero, ie writing
0xaaaaaaaa to a page buffer location that has the value 0x00000000, will not change the page
buffer value. The only way to change a bit from zero to one, is to reset the entire page buffer with
the Clear Page Buffer command.
The page buffer is not automatically reset after a page write. The programmer should do this
manually by issuing the Clear Page Buffer flash command. This can be done after a page write,
or before the page buffer is loaded with data to be stored to the flash page.
Example: Writing a word into word address 130 of a flash with 128 words in the page buffer.
PAGEN will be updated with the value 1, and the word will be written into word 2 in the page
buffer.
This can be used for EEPROM emulation, i.e. writes with granularity of one word instead of an
entire page. Only words that are in an completely erased state (0xFFFFFFFF) can be changed.
The procedure is as follows:
The None offers a command set to manage programming of the flash memory, locking and
unlocking of regions, and full flash erasing. See chapter 12.8.3 for a complete list of commands.
To run a command, the field CMD of the Flash Command Register (FCMD) has to be written
with the command number. As soon as the FCMD register is written, the FRDY flag is automati-
cally cleared. Once the current command is complete, the FRDY flag is automatically set. If an
interrupt has been enabled by setting the bit FRDY in FCR, the interrupt line of the flash control-
ler is activated. All flash commands except for Quick Page Read (QPR) will generate an interrupt
request upon completion if FRDY is set.
After a command has been written to FCMD, the programming algorithm should wait until the
command has been executed before attempting to read instructions or data from the flash or
writing to the page buffer, as the flash will be busy. The waiting can be performed either by poll-
ing the Flash Status Register (FSR) or by waiting for the flash ready interrupt. The command
written to FCMD is initiated on the first clock cycle where the HSB bus interface in FLASHC is
IDLE. The user must make sure that the access pattern to the FLASHC HSB interface contains
an IDLE cycle so that the command is allowed to start. Make sure that no bus masters such as
DMA controllers are performing endless burst transfers from the flash. Also, make sure that the
1. Clear page buffer
2. Write to the page buffer the result of the logical bitwise AND operation between the
3. Write Page.
contents of the flash page and the new data to write. Only words that were in an erased
state can be changed from the original page.
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