User`s guide

LZ87010 Advance User’s Guide Analog Outputs (DAC)
1/15/03 14-3
14.1.2 Waveform Generator
The waveform generator can send a new value to the DAC automatically, on each cycle of its
selected input clock. This clock can be external, on the WFGIN0 or WFGIN1 pin, or internal,
using the output of one of the Timer 2-5 Compare units. The waveform generator has a select-
able step size and a programmable interrupt rate. See Figure 14-2. An index register allows
patterns to begin at any point in waveform memory, and multiple patterns may be stored if
desired. Patterns can wrap around from the end of the 128-byte memory to the beginning.
The processor can write also directly to a DAC if the waveform feature is not desired.
The waveform generator can be clocked at speeds of up to PCLK/2.
Figure 14-2. Effect of Step Values in Waveform Generation
1
0
50
100
150
200
250
300
81522293643
NOTE:
STEP = 1
STEP = 8
STEP = 32
DAC OUTPUT VALUE
50
57
64
WAVEFORM GENERATOR RAM TABLE INDEX
71 78 85 92 99 106
LZ87010-79
113 120 127