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8-1
CHAPTER 8
FREQUENCY GENERATOR
The 8XC196MD has a peripheral not found on other 8XC196Mx devices — the frequency gen-
erator. This peripheral produces a waveform with a fixed duty cycle (50%) and a programmable
frequency (ranging from 4 kHz to 1 MHz with a 16-MHz input clock). One application for the
frequency generator is to drive an infrared LED to transmit remote control data and control sig-
nals.
This chapter describes the frequency generator and explains how to configure it. For detailed de-
scriptions of the signals discussed in this chapter, refer to Appendix B, “Signal Descriptions.” For
additional information and application examples, consult AP-483, Application Examples Using
the 8XC196MC/MD Microcontroller (order number 272282).
8.1 FUNCTIONAL OVERVIEW
The frequency generator (Figure 8-1) has a frequency register, a count register, and an output sig-
nal. The output signal shares pin P7.7, so you must configure the pin for its frequency generator
output function.
Figure 8-1. Frequency Generator Block Diagram
A2702-01
Down-
Counter
FREQ_GEN
Count = 0
Load
D
C
Q#
Q
Port 7
Control
P7_MODE
P7_DIR
P7_REG
P7.7/FREQOUT
8
8
8
FREQ_CNT