Name

ID

Command Code

D/C

Function

Def.

F8

100 101X-0011-X

C Time base clock output: 8Hz

The WDT time-out flag after: 1/2 s

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

A6~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 except for the

first command will be omitted. The source of the tone frequency and of the time base/WDT clock fre-

quency can be derived from an on-chip 32kHz RC oscillator, a 32.768kHz crystal oscillator, or an ex-

ternal 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 HT1623 after power on reset,

for power on reset may fail, which in turn leads to the malfunctioning of the HT1623.

HT1623

17

April 21, 2000