AT43USB326-AC Atmel, AT43USB326-AC Datasheet - Page 9

• 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

SRAM Data
Memory
3313D–USB–04/06
Table 3 summarizes how the AT43USB326 SRAM Memory is organized. The lower 608 Data
Memory locations address the Register file, the I/O Memory and the internal data SRAM. The
first 96 locations address the Register File + I/O Memory, and the next 512 locations address
the internal data SRAM. The five different addressing modes for the data memory cover:
Direct, Indirect with Displacement, Indirect, Indirect with Pre-decrement and Indirect with Post-
increment. In the register file, registers R26 to R31 feature the indirect addressing pointer reg-
isters. Direct addressing reaches the entire data space.
The Indirect with Displacement mode features 63 address locations that reach from the base
address given by the Y- or Z-register.
When using register indirect addressing modes with automatic pre-decrement and post-incre-
ment, the address registers X, Y, and Z are decremented and incremented.
The 32 general-purpose working registers, 64 I/O registers and the 512 bytes of internal data
SRAM in the AT43USB326 are all accessible through these addressing modes.
To manage the USB hardware, a special set of registers is assigned. These registers are
mapped to SRAM space between addresses $1F00 and 1FFF. Table 3 and Table 4 give an
overview of these registers.
AT43USB326
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