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09/22/00

GL603USB/GL603USB-A/GL603USB-B

Revision 1.4

The GL603USB provides the unique “Full-Range Detection” ability. Over 95% of PC mouse market adopts

photo-sensor system to detect the mechanical movement of the roller inside the mouse. Because the

sensors may have varied characteristic on their output DC voltage level and output moving range, the

mouse manufacturers can’t avoid the expensive process of matching LED and photo-sensor. By providing

those photo-input pins with full-range detection function, the mouse makers can ignore the range difference

between those sensors, so the manufacturing procedure is simple and a huge cost is saved on the

manufacturing line.

By detecting the output signal came from the sensors, Genesys Lo gic’s patented algorithm could learn the

tiny difference of every signal and automatically adjust the threshold for the sensors without any side effect.

This new outstanding design can help the manufacturers decrease their inconvenience on mass -production

line and cut their human and mechanical cost tremendously.

There’s a 4-bit Analog-to-Digital Converter (ADC) module in the GL603USB. The input signal of ADC

can be connected to Port 2.0 ~ Port 2.7. When these I/O pins is used for analog input, the corre sponding

bits in DMODE register should be set to 0 to disable input buffer of Port 2. This can save power consumed

by the pad of Port 2. The PHSEL register is used to select which input connected to the ADC and the

PHVAL register is used to store the digital value converted by the ADC. The Genesys Logic’s proprietary

algorithm can detect any analog waveform from photo-sensor with amplitude larger than 1V. The ADC is a

high-speed converter. It takes less than 500ns to complete the conversion. Because GL603USB is running

at 3 MIPS for USB low speed application, only two dummy instructions should be added between write

PHSEL to read PHVAL.

4.5

CLOCK GENERATOR

The GL603USB build in a clock generator circuit to generate the 12 MHz clock for micro-controller and 6

MHz clock for USB engine use. The clock generator is enabled only when bit 1 of PORTCON1 is cleared.

With the clock generator, we can only use a 6 MHz ceramic resonator or crystal to reduce EMI. The clock

generator can be disabled by code option. When the clock generator is disabled, the 6 MHz clock is used by

micro-controller and USB engine directly. When 12 MHz resonator or crystal is used, the 12 MHz clock is

directly used by micro-controller and divided by 2 before used by USB engine. The clock division can be

programmed by another code option when 12 MHz ceramic resonator or crystal is used.

4.6

GENERAL PURPOSE I/O PORTS

Interface with peripherals is conducted via up to 15 GPIO signals. These 15 signals are divided into two

ports: Port 1 and Port 2. Port 1 contains seven lines (PORT1.0-PORT1.6) and Port 2 contains eight lines

(PORT2.0-PORT2.7). The Port 1 data register is located at data memory address 06h while the Port 2 data

register is located at data memory address 07h.

Port 2 is a low current port with analog input capability suitable for connecting photo-sensor. Port 1 is a

high current port capable of LED drive. PORT1.5 and PORT1.6 (which is combined with USB D+/D-) are

open drain output. Therefore, they can only drive low at output mode and extern al pulled up resistor should

be added. This is enough for PS/2 CLK and DATA. Except these 2 GPIO lines, each GPIO line may

include an internal pull-up or pull-down resistor. Port 2’s internal pull-down resistor value can be

programmed by option-code. Each output drive has slew-rate control to reduce EMI. Please see the

following table for details.

Driving capability

Pull-up resistor

Pull-down resistor

PORT1.0

20 mA

PORT1.1

20 mA

PORT1.2

4 mA

10K

Ω