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

A7~A0 : RAM address

D3~D0 : RAM data

D/C : Data/Command mode

Def. : Power on reset denault

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, a 32.768kHz

crystal oscillator, or an external 32kHz clock. Calculation of the frequency is based on the sys-

tem frequency sources as stated above. It is recommended that the host controller should ini-

tialize the HT1626 after power on reset, for power on reset may fail, which in turn leads to the

malfunctioning of the HT1626.

HT1626

16

April 21, 2000