Holtek Semiconductor Inc HT6513B Datasheet
HT6513
Mouse Controller
Pin Assignment
Features
•
Low power dissipation
•
Use 32.768KHz crystal
•
Crystal oscillator circuits on-chip
•
1200 baud rate serial output
•
Power directly from RS-232C without external power supply
•
Three key-switches a nd four photo-couples
inputs
•
Key-in and key-release debounce interval 52 ms
•
The HT6513 can execute two different
outputs with any of the key-switch inputs
•
RXD with heavy NMOS output
General Description
The HT6513 is a specially designed CMOS IC
for mouse control applications. Capable of driving up to 3 key-switches a nd 4 photo-couplers
directly into a standard RS-232C line, and it
can be operated without an external power supply. It is compatible with both Microsoft and
Mouse systems with false entries being prevented by internal debounce circuits.
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Block Diagram
Pin Description
Pin Name I/O
Internal
connection
Description
MS I —
When this pin is connected to VDD , then HT65 13 is assi gned
to operate under the microsoft mode only. If the pin is
connected to VSS, then HT6513 wi ll ope rate under th e m ouse
system mode. If MS pin is “floating”, the HT6513 is on the
power on initiation mode.
TEST I Pull-Low
For IC test only. The test pin must be connected to VSS, while
the chip is under normal usage.
OSCI I — Oscillator input pin
OSCO O — Oscillator output pin
RTS I —
The signal is sent b y the mouse driver from the computer to
select the mode.
The HT6513 re plies with the selected m ode to the RXD line
after the puls e signal of the RTS l ine. RXD wi ll send out “ CD”H
code under the microsoft mode.
RXD O
NMOS
Open Drain
There are 7 or 8 bits in each data byte. Using p arallel-in and
serial-out circuit, the data bytes are shifted out from bit 0
through the most significant bit. HT6513 will transmit the
data when the s tatus of the three ke y-switches or the state of
the horizontal counter or vertical counter change.
VSS I — Negative power supply
HT6513
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Pin Name I/O
Internal
connection
Description
R
M
L
IPull-Low
Three key-switches have seven different combinations in total.
Both key-pressed and key-released signals will be sent
accompanied with horizo ntal and ve rtical state. The status of
the key-switches, the value s of h orizon tal or ve rtical co unters
will be present at RXD and
RXD. The debounce interval for
both key-press and key-release is 13ms.
X1
X2
Y1
Y2
I—
Four photo-couplers signals denote UP, DOWN, LEFT, and
RIGHT state.
During the scaning period, as long as the photo-couplers
change their states, the value of vertical or horizon tal counte r
will increase or decrease accordingly.
VDD I — Position power supply
Approximate Internal connection circuits
HT6513
3 23rd Oct ’96
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