Buzzer Circuit Operation - Oki ML63611 User Manual

ML63611 User's Manual
Chapter 11 Melody Driver (MELODY)
11.5

Buzzer Circuit Operation

When EMBD (bit 2 of MDCON) is set to "1", a buzzer driver signal is sent to the melody driver output pins (MD,
MDB).
Four buzzer output modes can be selected by MBM1 (bit 1 of MDCON) and MBM0 (bit 0 of MDCON): two
types of intermittent tones, a single tone, or a continuous tone output. The buzzer output frequency is 4 kHz and
has a 50% duty ratio.
In the intermittent tone 1 mode, a waveform synchronized to the 8 Hz output of the time base counter is output.
In the intermittent tone 2 mode, a waveform synchronized to the logical AND of 8 Hz signal output and a "L"
level of 1 Hz signal of the time base counter is output.
In the single tone mode, output starts in synchronization with the rising edge of EMBD. At the second falling
edge of the 32 Hz output of the time base counter, EMBD is cleared to "0" and output is stopped.
In the continuous tone mode, output is continued while EMBD is "1".
While the melody is being output (MSF (bit 3 of MDCON) = "1"), the buzzer output is turned OFF. If melody
output is started during buzzer output, EMBD is cleared to "0", the buzzer output is stopped, and melody output is
given priority.
Figure 11-5 shows the output waveforms of each mode. Shaded sections indicate the 4 kHz output frequency.
OPTION A (C): 1.5 V (3.0 V), Without regulator
circuit for LCD bias
11 – 10
OPTION B (D): 1.5 V (3.0 V), With regulator
circuit for LCD bias