HT82K629A-40DIPLF HOLTEK, HT82K629A-40DIPLF Datasheet - Page 6

• Manufacturer Part Number: HT82K629A-40DIPLF
• Description: IC, USB/PS2 CONT, WIN 2000 KEYBOARD
• Manufacturer: HOLTEK

Specifications of HT82K629A-40DIPLF

• Usb Type: Keyboard Encoder
• Usb Version: 1.1
• Supply Voltage Range: 4.4V To 5.5V
• Operating Temperature Range: 0°C To +70°C
• Digital Ic Case Style: DIP
• No. Of Pins: 40
• Operating Temperature Max: 70°C
• Base Number: 82
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Commands to the Host
The following table shows the commands that the
HT82K629A may send to the host and their hexadeci-
mal values.
00H or FFH - Key Detection Error
The HT82K629A sends a key detection error character if
conditions in the keyboard make it impossible to identify
a switch closure. If the HT82K629A is using scan code
set 1, the code is FFH. For sets 2, the code is 00H.
00H or FFH - Overrun
An overrun character is placed in the HT82K629A buffer
and replaces the last code when the buffer capacity has
been exceeded. The code is sent to the host when it
reaches the top of the buffer queue. If the HT82K629A is
using scan code set 1, the code is FFH. For sets 2, the
code is 00H.
83AbH - Keyboard ID
The keyboard ID consists of 2 bytes, Hex 83AbH. The
HT82K629A responds to the Read ID with ACK, discon-
tinues scanning and sends 2 ID bytes. The low byte is
sent first followed by the high byte. Following the output
of Keyboard ID, the HT82K629A begins scanning.
EEH - Echo
The HT82K629A sends this code in response to an
Echo command.
AAH - BAT Completion Code
Following a satisfactory completion of the BAT, the
HT82K629A sends AAH. Any other code indicates key-
board failure.
FCH - BAT Failure Code
If a BAT failure occurs, the HT82K629A sends this code,
discontinues scanning and waits for a host response or
reset.
FEH - Resend
The HT82K629A issues a Resend command following
receipt of an invalid input or any input with incorrect par-
ity. If the host sends nothing to the HT82K629A, no re-
sponse is required.
Rev. 1.40
Key Detection Error/Overrun
Keyboard ID
Bat Completion Code
Bat Failure Core
Echo
Acknowledge
Resend
Key Detection Error/Overrun
Command
FF (Code Set 1)
00 (Code Set 2)
Hex Value
83AB
AA
FC
EE
FA
FE
6
Data Communications
Data Stream
Note:
B1
B2
B3
B4
B5
B6
B7
B8
B9
B10
B11
Data output
Data input
If the keyboard data line is found to be at an inactive
level following the 10th bit, a frame error has occurred,
and the keyboard continues to count until the data
line becomes active. The keyboard then makes the
data line inactive and sends a Resend.
If CLK=0, no transmission (keyboard is inhibited).
If CLK=1, DATA=0, no transmission (system re-
quest to send).
If CLK=1, DATA=1, transmission permitted.
Data will be valid before the trailing edge and be-
yond the leading edge of the clock.
The KB checks the clock line for an active level ev-
ery 60ms.
If line contention occurs (system brings the clock
low before the tenth clock), set clock=data=high.
The system overrides the clock line for at least
60ms.
The keyboard checks the clock line state at inter-
vals of 10ms.
If a system request-to-send is detected, the key-
board counts 11 data bits.
Data will be valid before the rising edge and beyond
the falling edge.
After the 10th bit, the keyboard checks for an active
level on the data line. If the line is active it is forced
to be inactive, and counts one more bits.
Note: This action signals the system that the
The parity bit is either 1 or 0, and the 8 data bits,
plus the parity bit, always have an odd number
of 1 s.
reception of this signal, the system returns
keyboard has received its data. Upon
to the ready state, in which it can accept
keyboard outputs or goes to the inhibit
state until it is ready.
Start bit (always 0)
Data bit 0
Data bit 1
Data bit 2
Data bit 3
Data bit 4
Data bit 5
Data bit 6
Data bit 7
Parity bit (odd par)
Stop bit (always 1)
Mode 1,2,3
September 15, 2004
HT82K629A