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09/22/00

GL603USB/GL603USB-A/GL603USB-B

Revision 1.4

2

FUNCTIONAL OVERVIEW

The GL603USB is a 8-bits RISC-like high performance microcontroller with a built-in 1.5Mbps SIE and

transceiver. The microcontroller features 33 instructions optimized for USB and PS/2 mouse. There are 64

bytes on-chip RAM and 2.75K x 14 program ROM incorporated into the microcontroller. Because the

GL603USB build in a clock generator circuit, it can accepts a 6 MHz ceramic resonator or a crystal as its

clock source. The clock generator can generate 12 MHz clock for micro-controller to sense mouse tracking

signal. The clock is only enabled when bit 1 of PORTCON1 register is cleared. In default firmware, it

indicates the controller is running on PS/2 mouse mode. The sampling rate of mouse tracking signal can be

up to 100 us in USB mode and 80 us in PS/2 mode. The micro-controller features 13 general purpose I/Os

(GPIOs). 8 GPIO pins build in 4 bits ADC for photo-sensor input to remove the expensive process of

matching LED and photo-sensor. Additionally, 2 GPIO pins are strong enough to drive LEDs. The other 3

GPIO pins is used for mouse buttons by default firmware. Beside the 13 GPIO pins, another 2 GPIO pins

combined with USB D+/D- functions can be used as DATA and CLK in PS/2 mode. Legacy USB cable

can be used for mouse in USB mode and an USB to PS/2 converter is required in PS/2 mode. All GPIO

ports feature low EMI emissions as a result of improved output drivers with slew-rate control.

Micro-

controller

USB Registers

&

FIFO Control

Endpoint 0

8 Bytes FIFO

Endpoint 1

8 Bytes FIFO

USB

Interface

D+

D-

PS/2 CLK

Mux

PS/2 DATA

Select Control

D+ / PS2CLK

D- / PS2DATA

Figure 2-1 Block Diagram of GL603USB