GL603USB View Datasheet(PDF) - Genesys Logic
Part Name
Description
MFG CO.
'GL603USB' PDF : 41 Pages View PDF
GL603USB/GL603USB-A/GL603USB-B
PORT1.3
4 mA
10KΩ
PORT1.4
4 mA
10KΩ
PORT1.5
4 mA (open drain)
PORT1.6
PORT2.0
4 mA (open drain)
4 mA
4KΩ/8KΩ/16KΩ/32KΩ [1]
PORT2.1
4 mA
4KΩ /8KΩ /16KΩ /32KΩ
PORT2.2
4 mA
4KΩ /8KΩ /16KΩ /32KΩ
PORT2.3
4 mA
4KΩ /8KΩ /16KΩ /32KΩ
PORT2.4
4 mA
4KΩ /8KΩ /16KΩ /32KΩ
PORT2.5
4 mA
4KΩ /8KΩ /16KΩ /32KΩ
PORT2.6
4 mA
4KΩ /8KΩ /16KΩ /32KΩ
PORT2.7
4 mA
4KΩ /8KΩ /16KΩ /32KΩ
Note 1: The pull-down resistor can be configured as 4KΩ, 8KΩ, 16KΩ or 32KΩ by option-code.
Table 4-3 General Purpose I/O Port Summary
4.7 TIMER INTERRUPT
The Timer Interrupt is generated when the TIMER register overflows from FFh to 00h. This overflow sets
bit TMROF (INTEN<2>). The interrupt can be masked by clearing bit TMROEN (INTEN<5>). Bit
TMROF must be cleared in software by the Timer module interrupt service routine otherwise the Timer
Interrupt will not be generated again. If prescaler is disabled, the timer register will increase every
instruction cycle. If prescaler is enabled, its increment cycle depends on PS0~PS2 bits in PSCON register.
4.8 USB ENGINE
The USB module contains three functional blocks: a 3.3-volt regulator, a low-speed USB transceiver, and
the Serial Interface Engine (SIE). The USB module is only enabled under USB mode. While the mouse is
working under PS/2 mode, the USB module is disabled and D+/D- working as open drain GPIO pins. The
following details the function of the regulator, transceiver, and SIE.
4.8.1 Voltage Regulator
The USB data lines are required by the USB specification to have a maximum output voltage between 2.8V
and 3.6V. Because the GL603USB is a low speed USB device, the D- lines also are required to have an
external 1.5-kΩ pull-up resistor connected between a data line and a voltage source between 3.0 V and 3.6
V. Since the power provided by the USB cable is specified to be between 4.4V and 5.0V, an on-chip
regulator is used to drop the voltage to the appropriate level for sourcing the USB transceiver and external
pull-up resistor. An output pin driven by the regulator is provided to source the 1.5-kΩ external resistor.
4.8.2 USB Transceiver
The USB transceiver provides the physical interface to the USB D+ and D- data lines. The transceiver is
composed of two parts: an output driver circuit and a receiver.
The USB transceiver uses a differential output driver to driver the USB data signal onto the USB cable. The
static output swing of the driver in its low state is below the VOL of 0.3V with 1.5-kΩ load to 3.6V and in
its high state is above the VOH of 2.8V with 15-kΩ load to ground. The output swings between the
differential high and low state are well balanced to minimize signal skew. Slew rate control on the driver is
used to minimize the radiated noise and cross talk. The driver’s outputs support 3-state operation to achieve
bi-directional half-duplex operation. The driver can tolerate a voltage on the signal pins of –0.5V to 3.8V
with respect to local ground reference without damage.
22
09/22/00
Revision 1.4
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