Name

ID

Command Code

D/C

Function

Def.

TONE 4K

100 010X-XXXX-X

C

Tone frequency output: 4kHz

TONE 2K

100 0110-XXXX-X

C

Tone frequency output: 2kHz

IRQ DIS

100 100X-0XXX-X

C

Disable IRQ output

Yes

IRQ EN

100 100X-1XXX-X

C

Enable IRQ output

F1

100 101X-0000-X

C

Time base clock output: 1Hz

The WDT time-out flag after: 4s

F2

100 101X-0001-X

C

Time base clock output: 2Hz

The WDT time-out flag after: 2s

F4

100 101X-0010-X

C

Time base clock output: 4Hz

The WDT time-out flag after: 1s

F8

100 101X-0011-X

C

Time base clock output: 8Hz

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

F16

100 101X-0100-X

C

Time base clock output: 16Hz

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

F32

100 101X-0101-X

C

Time base clock output: 32Hz

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

F64

100 101X-0110-X

C

Time base clock output: 64Hz

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

F128

100 101X-0111-X

C

Time base clock output: 128Hz

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

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 or 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 system frequency sources as stated above. It is recommended that the host control-

ler should initialize the HT1625 after power on reset, for power on reset may fail, which in turn leads to the mal-

functioning of the HT1625.

HT1625

Rev. 1.10

13

September 11, 2002