HT1621
Name
RC 256K
ID
Command Code
D/C
C
Function
Def.
1 0 0 0001-10XX-X
1 0 0 0001-11XX-X
System clock source, on-chip RC oscillator Yes
System clock source, external clock source
EXT 256K
C
LCD 1/2 bias option
ab=00: 2 commons option
ab=01: 3 commons option
ab=10: 4 commons option
BIAS 1/2
1 0 0 0010-abX0-X
1 0 0 0010-abX1-X
C
C
LCD 1/3 bias option
ab=00: 2 commons option
ab=01: 3 commons option
ab=10: 4 commons option
BIAS 1/3
TONE 4K
TONE 2K
IRQ DIS
IRQ EN
1 0 0 010X-XXXX-X
1 0 0 011X-XXXX-X
1 0 0 100X-0XXX-X
1 0 0 100X-1XXX-X
C
C
C
C
Tone frequency, 4kHz
Tone frequency, 2kHz
Disable IRQ output
Enable IRQ output
Yes
Time base/WDT clock output:1Hz
The WDT time-out flag after: 4s
F1
1 0 0
101X-X000-X
C
C
C
C
C
C
C
C
Time base/WDT clock output:2Hz
The WDT time-out flag after: 2s
F2
1 0 0 101X-X001-X
Time base/WDT clock output:4Hz
The WDT time-out flag after: 1s
F4
1 0 0
101X-X010-X
Time base/WDT clock output:8Hz
The WDT time-out flag after: 1/2s
F8
1 0 0 101X-X011-X
1 0 0 101X-X100-X
1 0 0 101X-X101-X
1 0 0 101X-X110-X
1 0 0 101X-X111-X
Time base/WDT clock output:16Hz
The WDT time-out flag after: 1/4s
F16
F32
F64
F128
Time base/WDT clock output:32Hz
The WDT time-out flag after: 1/8s
Time base/WDT clock output:64Hz
The WDT time-out flag after: 1/16s
Time base/WDT clock output:128Hz
The WDT time-out flag after: 1/32s
Yes
Yes
TEST
1 0 0 1110-0000-X
1 0 0 1110-0011-X
C
C
Test mode, user don¢t use.
NORMAL
Normal mode
Note: X : Don,t care
A5~A0 : RAM addresses
D3~D0 : RAM data
D/C : Data/command mode
Def. : Power on reset default
All the bold forms, namely 1 1 0, 1 0 1, and 1 0 0, are mode commands. Of these, 1 0 0 indicates the command
mode ID. If successive commands have been issued, the command mode ID except for the first command will
be omitted. The source of the tone frequency and of the time base/WDT clock frequency can be derived from
an on-chip 256kHz RC oscillator, a 32.768kHz crystal oscillator, or an external 256kHz clock. Calculation of the
frequency is based on the system frequency sources as stated above. It is recommended that the host control-
ler should initialize the HT1621 after power on reset, for power on reset may fail, which in turn leads to the mal-
functioning of the HT1621.
Rev. 1.30
13
August 6, 2003
HOLTEK [ HOLTEK SEMICONDUCTOR INC ]
