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Features
AVR
8-bit RISC Microcontroller with 83 ns Instruction Cycle Time
USB Hub with One Attached and Two External Ports
USB Keyboard Function with Three Programmable Endpoints
16 KB Program Memory, 512 Bytes Data SRAM
32 x 8 General-purpose Working Registers
32 Programmable I/O Port Pins
Support for 18 x 8 Keyboard Matrix
Keyboard Scan Inputs with Pull-up Resistor
Four LED Driver Outputs
One 8-bit Timer/Counter with Separate Pre-scaler
External and Internal Interrupt Sources
Programmable Watchdog Timer
6 MHz Oscillator with On-chip PLL
5V Operation with On-chip 3.3V Power Supply
48-lead LQFP Package
Description
The Atmel AT43USB326 is an 8-bit microcontroller based on the AVR RISC architec-
ture. By executing powerful instructions in a single clock cycle, the AT43USB326
achieves throughputs approaching 12 MIPS. The AVR core combines a rich instruc-
tion set with 32 general-purpose working registers. All 32 registers are directly
connected to the ALU allowing two independent registers to be accessed in one single
instruction executed in one clock cycle. The resulting architecture is more code effi-
cient while achieving throughputs up to ten times faster than conventional CISC
microcontrollers.
Furthermore, the AT43USB326 features an on-chip 16-Kbyte program memory and
512 bytes of data memory. It is supported by a standard set of peripherals such as
timer/counter modules, watchdog timer and internal and external interrupt sources.
The major peripheral included in the AT43USB326 is the USB Hub with an embedded
keyboard controller function.
Multimedia
USB Keyboard
Controller with
Embedded Hub
AT43USB326
Rev. 3313AUSB01/03
4
AT43USB326
3313AUSB01/03
Signal Description
Name
Type
Function
V
CC
Power Supply/Ground
5V Digital Power Supply
V
SS1
,
2
Power Supply/Ground
Ground
CEXT1, 2
Power Supply/Ground
External Capacitors for Power Supplies High quality 2.2 F capacitors must be
connected to CEXT1 and 2 for proper operation of the chip.
XTAL1
Input
Oscillator Input Input to the inverting oscillator amplifier.
XTAL2
Output
Oscillator Output Output of the inverting oscillator amplifier.
LFT
Input
PLL Filter For proper operation of the PLL, this pin should be connected through
a 0.01 F capacitor in parallel with a 100
resistor in series with a 0.1 F capacitor
to ground (VSS). Both capacitors must be high quality ceramic.
DPO
Bi-directional
Upstream Plus USB I/O This pin should be connected to CEXT1 through an
external 1.5 k
.
DMO
Bi-directional
Upstream Minus USB I/O
DP[2,3]
Bi-directional
Downstream Plus USB I/O Each of these pins should be connected to VSS
through an external 15 k
resistor. DP[2,3] and DM[2,3] are the differential signal
pin pairs to connect downstream USB devices.
DM[2,3]
Bi-directional
Downstream Minus USB I/O Each of these pins should be connected to VSS
through an external 15 k
resistor.
PA[0:7]
Bi-directional
Port A[0:7] Bi-directional 8-bit I/O port with controlled slew rate. These pins are
used as eight of the keyboard matrix column output strobes. PA[0:7] = COL[0:7].
PB[0:7]
Bi-directional
Port B[0:7] Bi-directional 8-bit I/O port controlled slew rate. These pins are used
as the eight of the keyboard matrix column output strobes: PB[0:7] = COL[8:15].
PC[0:7]
Bi-directional
Port C[0:7] Bi-directional 8-bit I/O port with internal pull-ups. These pins are used
as keyboard matrix row input signals. PC[0:7] = ROW [0:7].
PD[0:1]
Bi-directional
Port D[0:1] Bi-directional I/O ports.
PE[0:1]
Bi-directional
Port E[0:1] Bi-directional I/O port with controlled slew rate which can be used as
two additional keyboard column output strobes, COL 16, 17.
PE[4:7]
Bi-directional
PE[4:7] have built-in series limiting resistors and can be used to drive LEDs
directly.
TEST
Input
Test Pin This pin should be tied to ground.
RESETN
Input
Reset Active Low.
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