Datasheet
Table Of Contents
- Features
- 1. Ordering Information
- 2. Pinout/Block Diagram
- 3. Overview
- 4. Resources
- 5. Capacitive touch sensing
- 6. AVR CPU
- 7. Memories
- 8. Event System
- 9. System Clock and Clock options
- 9.1 Features
- 9.2 Overview
- 9.3 Clock Sources
- 9.3.1 32kHz Ultra Low Power Internal Oscillator
- 9.3.2 32.768kHz Calibrated Internal Oscillator
- 9.3.3 32.768kHz Crystal Oscillator
- 9.3.4 0.4 - 16MHz Crystal Oscillator
- 9.3.5 2MHz Run-time Calibrated Internal Oscillator
- 9.3.6 32MHz Run-time Calibrated Internal Oscillator
- 9.3.7 External Clock Sources
- 9.3.8 PLL with 1x-31x Multiplication Factor
- 10. Power Management and Sleep Modes
- 11. System Control and Reset
- 12. WDT – Watchdog Timer
- 13. Interrupts and Programmable Multilevel Interrupt Controller
- 14. I/O Ports
- 15. TC0/1 – 16-bit Timer/Counter Type 0 and 1
- 16. TC2 – Timer/Counter Type 2
- 17. AWeX – Advanced Waveform Extension
- 18. Hi-Res – High Resolution Extension
- 19. RTC – 16-bit Real-Time Counter
- 20. USB – Universal Serial Bus Interface
- 21. TWI – Two-Wire Interface
- 22. SPI – Serial Peripheral Interface
- 23. USART
- 24. IRCOM – IR Communication Module
- 25. CRC – Cyclic Redundancy Check Generator
- 26. ADC – 12-bit Analog to Digital Converter
- 27. AC – Analog Comparator
- 28. Programming and Debugging
- 29. Pinout and Pin Functions
- 30. Peripheral Module Address Map
- 31. Instruction Set Summary
- 32. Packaging information
- 33. Electrical Characteristics TBD
- 34. Typical Characteristics TBD
- 35. Errata
- 36. Datasheet Revision History
- Table of Contents

15
8493A–AVR–02/12
XMEGA C4
7.9 Device ID and Revision
Each device has a three-byte device ID. This ID identifies Atmel as the manufacturer of the
device and the device type. A separate register contains the revision number of the device.
7.10 I/O Memory Protection
Some features in the device are regarded as critical for safety in some applications. Due to this,
it is possible to lock the I/O register related to the clock system, the event system, and the
advanced waveform extensions. As long as the lock is enabled, all related I/O registers are
locked and they can not be written from the application software. The lock registers themselves
are protected by the configuration change protection mechanism.
7.11 Flash and EEPROM Page Size
The flash program memory and EEPROM data memory are organized in pages. The pages are
word accessible for the flash and byte accessible for the EEPROM.
Table 7-2 on page 15 shows the Flash Program Memory organization and Program Counter
(PC) size. Flash write and erase operations are performed on one page at a time, while reading
the Flash is done one byte at a time. For Flash access the Z-pointer (Z[m:n]) is used for address-
ing. The most significant bits in the address (FPAGE) give the page number and the least
significant address bits (FWORD) give the word in the page.
Table 7-2. Number of words and pages in the flash.
Table 7-3 shows EEPROM memory organization. EEEPROM write and erase operations can be
performed one page or one byte at a time, while reading the EEPROM is done one byte at a
time. For EEPROM access the NVM address register (ADDR[m:n]) is used for addressing. The
most significant bits in the address (E2PAGE) give the page number and the least significant
address bits (E2BYTE) give the byte in the page.
Table 7-3. Number of bytes and pages in the EEPROM.
Devices PC size Flash size Page size FWORD FPAGE Application Boot
[bits] [bytes] [words] Size No of pages Size No of pages
ATxmega16C4 17 16K + 8K 128 Z[6:0] Z[13:7] 46K 64 4 16
ATxmega32C4 18 32K + 8K 128 Z[6:0] Z[14:7] 32K 128 4K 16
Devices EEPROM Page size E2BYTE E2PAGE No of pages
size [bytes]
ATxmega16C4 2K 32 ADDR[4:0] ADDR[10:5] 32
ATxmega32C4 4K 32 ADDR[4:0] ADDR[10:5] 32