SS1621
p. 9
Last update: 2008-06-03 04:36
generator or of the WDT time-out flag appear
on the IRQ pin. The configuration of the time
base generator along with the WDT are as
shown. In the case of on-chip RC oscillator or
crystal oscillator, the power down mode can
reduce power consumption since the oscillator
can be turned on or off by the corresponding
system commands. At the power down mode
the time base/WDT loses all its functions.
On the other hand, if an external clock is
selected as the source of sys tem frequency
the SYS DIS command turns out invalid and
the power down mode fails to be carried out.
That is, after the external clock source is se-
lected, the SS1621 will continue working un-
til system power fails or the external clock
source is removed. After the system power on,
the IRQ will be disabled.
Tone output
A simple tone generator is implemented
in the SS1621. The tone generator can output
a pair of differential driving signals on the BZ
and BZ, which are used to generate a single
tone. By executing the TONE4K and
TONE2K commands there are two tone fre-
quency outputs selectable. The TONE4K and
TONE2K commands set the tone frequency to
4kHz and 2kHz, respectively. The tone output
can be turned on or off by invoking the TONE
ON or the TONE OFF command. The tone
outputs, namely BZ and BZ, area pair of dif-
ferential driving outputs used to drive a piezo
buzzer. Once the system is disabled or the
tone output is inhibited, the BZ and the BZ
output will remain at low level.
LCD driver
The SS1621 is a 128 (32x4) patterns
LCD driver. It can be configured as 1/2 or 1/3
bias and 2 or 3 or 4 commons of LCD driver
by the S/W configuration. This feature makes
the SS1621 suitable for multiply LCD appli-
cations. The LCD driving clock is derived
from the system clock. The value of the driv-
ing clock is always 256Hz even when it is at a
32.768kHz crystal oscillator frequency, or an
external frequency. The LCD corresponding
commands are summarized in the table.
The bold form of 100, namely 100, in-
dicates the command mode ID. If successive
commands have been issued, the command
mode ID except for the first command will be
omitted. The LCD OFF command turns the
LCD display off by disabling the LCD bias
generator. The LCD ON command, on the
other hand, turns the LCD display on by ena-
bling the LCD bias generator. The BIAS and
COM are the LCD panel related commands.
Using the LCD related commands; the
SS1621 can be compatible with most types of
LCD panels.
Command format
The SS1621 can be configured by the
S/W setting. There are two mode commands
to configure the SS1621 resources and to
transfer the LCD display data. The configura-
tion mode of the SS1621 is called command
mode, and its command mode IC is 100. The
command mode consists of system configura-
tion command, a system frequency selection
command, a LCD configuration command, a
tone
frequency
selection
command,
a
Name
Command Code
Function
LCD OFF
1 0 0 0 0 0 0 0 0 1 0 X
Turn off LCD outputs
LCD ON
1 0 0 0 0 0 0 0 0 1 1 X
Turn on LCD outputs
c=0:1/2 bias option
c=1:1/3 bias option
ab=00:2 commons option
ab=01:3 commons option
BIAS & COM 1 0 0 0 0 1 0 a b X c X
ab=10:4 commons option
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