10

06/19/2000

GL600USB/GL600USB-A/GL600USB-B

Revision 1.3

4

FUNCTIONAL DESCRIPTION

The Genesys Logic GL600USB microcontroller is optimized for USB 2D/3D/4D mouse. This USB

microcontroller conforms to the low-speed (1.5Mbps) requirements of the USB Specification version 1.1.

The microcontroller is a self-contained unit with an USB SIE, an USB transceiver, an 8-bits RISC-like

microcontroller, a timer, data and program memories. It supports one USB device address and two

endpoints (include endpoint 0).

4.1

MEMORY ORGANIZATION

The memory in the microcontroller is organized into user program memory in program ROM and data

memory in SRAM space.

4.1.1

Program Memory Organization

The 11-bit Program Counter (PC) is capable of addressing 2K x 14 of program space. However, the

program space of the GL600USB is 1.75K x 14. The program memory space is divided into two functional

groups: Interrupt Vectors and program code. After a reset, the Program Counter points to location zero of

the program space. After a timer interrupt, the Program Counter points the location 0x0004 of the program

space.

After Reset

→

Address

0x0000

Reset Vector

After Timer Interrupt

→

0x0004

Timer Interrupt Vector

0x0005

0x06FF

1.75K x 14 ROM

Figure 4-1 Program Memory Space

4.1.2

Data Memory Organization

The data memory is partitioned into two banks which contain the General Purpose Registers, MCU

Function Registers and USB Function Registers. Bit RP0 is the bank select bit.

RP0 (STATUS<5>) = 1

→ Bank 1

RP0 (STATUS<5>) = 0

→ Bank 0

The lower locations of each Bank are reserved for MCU Function Registers and USB Function Registers.

Above the MCU Function Registers and USB Function Registers are General Purpose Registers

implemented as SRAM. Both Bank 0 and Bank 1 contain MCU Function Registers. USB Function

Registers are located in Bank 0. Some “high use” MCU Function Registers from Bank 0 are mirrored in

Bank 1 for code reduction and quicker access.

Data Memory

Address

Data Memory

Address

00h

INDR

80h

INDR

01h

TIMER

81h

PSCON