Chapter 9 Buzzer Output Controller; Functions Of Buzzer Output Controllers - NEC mPD178054 Series User Manual

9.1 Functions of Buzzer Output Controllers

The µ PD178054 Subseries has the following two types of buzzer output controllers.
• BEEP0
• BUZ
BEEP0 outputs a square wave of the buzzer frequency selected by BEEP clock select register 0 (BEEPCL0) from
the BEEP0/P36 pin.
BUZ outputs a square wave of the buzzer frequency selected by the clock output select register (CKS) from the
BUZ/P37 pin.
Figures 9-1 and 9-2 show the block diagrams of BEEP0 and BUZ.
Remark f : System clock frequency
X

CHAPTER 9 BUZZER OUTPUT CONTROLLER

Figure 9-1. Block Diagram of BEEP0
1 kHz
1.5 kHz
Selector
3 kHz
4 kHz
BEEP BEEP
CL02 CL01
Internal bus
Figure 9-2. Block Diagram of BUZ
10
f /2
X
11
f /2
X
Selector
12
f /2
X
13
f /2
X
BZOE BCS1 BCS0
Internal bus
User's Manual U15104EJ2V0UD
BEEP0/P36
Output latch
PM36
(P36)
BEEP BEEP clock select
CL00 register 0 (BEEPCL0)
BUZ/P37
Output latch
PM37
(P37)
Clock output
select register (CKS)
127