Chapter 11 Buzzer Output Controller; Buzzer Output Controller Functions; Buzzer Output Controller Configuration - NEC mPD780208 Subseries User Manual

11.1 Buzzer Output Controller Functions

The buzzer output controller outputs a 1.2 kHz, 2.4 kHz, or 4.9 kHz frequency square-wave. The buzzer
frequency selected by timer clock select register 2 (TCL2) is output from the BUZ/P36 pin.
Follow the procedure below to output the buzzer frequency.
[1] Select the buzzer output frequency using bits 5 to 7 (TCL25 to TCL27) of TCL2.
[2] Set the P36 output latch to 0.
[3] Set bit 6 (PM36) of port mode register 3 (PM3) to 0 (set to output mode).
Caution Buzzer output cannot be used when the P36 output latch is set to 1.

11.2 Buzzer Output Controller Configuration

The buzzer output controller consists of the following hardware.
10
f /2
X
11
f /2
X
12
f /2
X
Timer clock select
register 2
186
CHAPTER 11 BUZZER OUTPUT CONTROLLER
Table 11-1. Buzzer Output Controller Configuration
Item
Control registers Timer clock select register 2 (TCL2)
Port mode register 3 (PM3)
Figure 11-1. Buzzer Output Controller Block Diagram
3
TCL27TCL26TCL25
User's Manual U11302EJ4V0UM
Configuration
P36
output PM36
latch
Internal bus
BUZ/P36
Port mode register 3