AT43USB326-AC Atmel, AT43USB326-AC Datasheet - Page 6

• Manufacturer Part Number: AT43USB326-AC
• Description: IC USB KEYBOARD CTRLR HUB 48LQFP
• Manufacturer: Atmel
• Series: AVR®r

Specifications of AT43USB326-AC

• Applications: Keyboard Controller
• Core Processor: AVR
• Program Memory Type: Mask ROM (16 kB)
• Controller Series: AT43USB
• Ram Size: 512 x 8
• Interface: USB
• Number Of I /o: 32
• Voltage - Supply: 4.4 V ~ 5.25 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 48-LQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Architectural
Overview
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AT43USB326
The AT43USB326 is a USB microcontroller with special peripherals for use as a programma-
ble keyboard controller.
The peripherals and features of the AT43USB326 microcontroller are similar to those of the
AT90S8515, with the exception of the following modifications:
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The embedded USB hardware of the AT43USB326 is a compound device, consisting of a 3
port hub with a permanently attached function on one port. The hub and attached function are
two independent USB devices, each having its own device addresses and control endpoints.
The hub has its dedicated interrupt endpoint, while the USB function has two additional pro-
grammable endpoints with 8-byte FIFOs.
The microcontroller always runs from a 12 MHz clock that is generated by the USB hardware.
While the nominal and average period of this clock is 83.3 ns, it may have single cycles that
deviate by ±20.8 ns during a phase adjustment by the SIE's clock/data separator of the USB
hardware.
The microcontroller shares most of the control and status registers of the megaAVR Microcon-
troller Family. The registers for managing the USB operations are mapped into its SRAM
space. The I/O section on page 14 summarizes the available I/O registers. The “AVR Register
Set” on page 34 covers the AVR registers. Please refer to the Atmel AVR manual for more
information.
The fast-access register file contains 32 x 8-bit general-purpose working registers with a sin-
gle clock cycle access time. This means that during one single clock cycle, one Arithmetic
Logic Unit (ALU) operation is executed. Two operands are output from the register file, the
operation is executed, and the result is stored back in the register file – in one clock cycle.
Six of the 32 registers can be used as three 16-bit indirect address register pointers for Data
Space addressing - enabling efficient address calculations. One of the three address pointers
is also used as the address pointer for look-up tables in program memory. These added func-
tion registers are the 16-bit X-, Y- and Z-registers.
The ALU supports arithmetic and logic operations between registers or between a constant
and a register. Single register operations are also executed in the ALU. Figure 2 on page 5
shows the AT43USB326 AVR Enhanced RISC microcontroller architecture.
In addition to the register operation, the conventional memory addressing modes can be used
on the register file as well. This is enabled by the fact that the register file is assigned the 32
lowest Data Space addresses ($00 - $1 F), allowing them to be accessed as though they were
ordinary memory locations.
The I/O memory space contains 64 addresses for CPU peripheral functions as Control Regis-
ters, Timer/Counters, and other I/O functions. The I/O Memory can be accessed directly, or as
the Data Space locations following those of the register file, $20 - $5F.
The AVR uses a Harvard architecture concept – with separate memories and buses for pro-
gram and data. The program memory is executed with a single-level pipelining. While one
A masked ROM for program memory
No EEPROM
No external data memory accesses
No UART
No SPI
No 16-bit timer/counter
Idle mode not supported
USB Hub with attached function
3313D–USB–04/06