Name

Command Code

D/C

Function

Def.

F8

X100-1010-0011-XXXX

C

Time base clock output: 8Hz

The WDT time-out flag after 1/2s

F16

X100-1010-0100-XXXX

C

Time base clock output: 16Hz

The WDT time-out flag after 1/4s

F32

X100-1010-0101-XXXX

C

Time base clock output: 32Hz

The WDT time-out flag after 1/8s

F64

X100-1010-0110-XXXX

C

Time base clock output: 64Hz

The WDT time-out flag after 1/16s

F128

X100-1010-0111-XXXX

C

Time base clock output: 128Hz

The WDT time-out flag after 1/32s

Yes

TEST

X100-1111-1111-XXXX

C

Test mode, not for use by the user

NORMAL

X100-1111-1110-XXXX

C

Normal mode, 64

´32 mode will be set

Yes

Note:

²X² stands for don¢t care

A8~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 tone frequency source and the time base or WDT clock frequency source 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 system frequency sources as stated above. It is recommended that the host control-

ler should initialize the HT1650 after power-on reset, otherwise, power on reset may fail, which in turn leads to

the malfunctioning of the HT1650.

HT1650

Rev. 1.20

16

November 10, 2005