HT1621
Name
ID
Command Code
D/C
Function
Enable IRQ output
Def.
IRQ EN
1 0 0 100X-1XXX-X
C
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
1 0 0 101X-X010-X
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:4Hz
The WDT time-out flag after: 1s
F4
Time base/WDT clock
output:8Hz
The WDT time-out flag after: 1/2 s
F8
Time base/WDT clock
output:16Hz
The WDT time-out flag after: 1/4 s
F16
F32
F64
F128
Time base/WDT clock
output:32Hz
The WDT time-out flag after: 1/8 s
Time base/WDT clock
output:64Hz
The WDT time-out flag after: 1/16 s
Time base/WDT clock
output:128Hz
The WDT time-out flag after: 1/32 s
Yes
Yes
TEST
1 0 0 1110-0000-X
1 0 0 1110-0011-X
C
C
Test mode, user don't use.
Normal mode
NORMAL
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 ex-
cept 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 controller should
initialize the HT1621 after power on reset, for power on reset may fail, which in turn leads to
the malfunctioning of the HT1621.
19
January 10, 2001
ETC [ ETC ]
