Name

ID

Command Code

D/C

Function

Def.

F16

100 101X-0100-X

C Time base clock output: 16Hz

The WDT time-out flag after: 1/4 s

F32

100 101X-0101-X

C Time base clock output: 32Hz

The WDT time-out flag after: 1/8 s

F64

100 101X-0110-X

C Time base clock output: 64Hz

The WDT time-out flag after: 1/16 s

F128

100 101X-0111-X

C Time base clock output: 128Hz

The WDT time-out flag after: 1/32 s Yes

TEST

100 1110-0000-X

C Test mode, user don t use.

NORMAL

100 1110-0011-X

C Normal mode

Yes

Note: X : Don t care

A5~A0 : RAM address

D3~D0 : RAM data

D/C : Data/Command mode

Def. : Power on reset default

All the bold forms, namely 110, 101, and 100, are mode commands. Of these, 100 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 32kHz RC oscillator or an external

32kHz 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 HT1622 after power on

reset, for power on reset may fail, which in turn leads to the malfunctioning of the HT1622.

HT1622

16

April 21, 2000