16 SOUND GENERATOR (SNDA)
16-2
Seiko Epson Corporation
S1C17M20/M21/M22/M23/M24/M25
TECHNICAL MANUAL (Rev. 1.0)
16.2 Output Pins and External Connections
16.2.1 List of Output Pins
Table 16.2.1.1 lists the SNDA pins.
Table 16.2.1.1 List of SNDA Pins
Pin name
I/O
*
Initial status
*
Function
BZOUT
O
O (Low)
Non-inverted buzzer output pin
#BZOUT
O
O (Low)
Inverted buzzer output pin
*
Indicates the status when the pin is configured for SNDA
If the port is shared with the SNDA pin and other functions, the SNDA output function must be assigned to the port
before activating the SNDA. For more information, refer to the “I/O Ports” chapter.
16.2.2 Output Pin Drive Mode
The drive mode of the BZOUT and #BZOUT pins can be set to one of the two types shown below using the SND-
SEL.SINV bit.
Direct drive mode (SNDSEL.SINV bit = 0)
This mode drives both the BZOUT and #BZOUT pins to low while the buzzer signal output is off to prevent the
piezoelectric buzzer from applying unnecessary bias.
Normal drive mode (SNDSEL.SINV bit = 1)
In this mode, the #BZOUT pin always outputs the inverted signal of the BZOUT pin even when the buzzer out-
put is off.
16.2.3 External Connections
Figures 16.2.2.1 and 16.2.2.2 show connection diagrams between SNDA and a piezoelectric buzzer.
BZOUT
#BZOUT
S1C17 SNDA
Piezoelectric
buzzer
Figure 16.2.2.1 Connection between SNDA and Piezoelectric Buzzer (Direct Drive)
BZOUT
S1C17 SNDA
Piezoelectric
buzzer
V
DD
Figure 16.2.2.2 Connection between SNDA and Piezoelectric Buzzer (Single Pin Drive)