W925E625 Datasheet, PDF (47/75 Pages) Winbond – 8-bit CID MICROCONTROLLER

W925E/C625
6.10 Comparator
A built-in comparator to compare the analog signal. There is a analog input paths from pin VNEG. Two
reference inputs, one is from pin VPOS and other is from regulator output. When the voltage of
positive input is higher than the negative input, the comparator output will be high. The
RESEC(COMPR.3) is the result of the comparison. An internal rising signal on RESC produces
interrupt flag of COMPF (EXIF.4). The flag COMPF is cleared when comparator interrupt routine is
executed or cleared by software. Set COMPEN to enable the comparator function.
VNEG(P4.2)
VPOS(P4.4)
REF1
REF
X.XV
REGULATOR
EN
C3
RESET
D
CK
Clr
D
RESC _CK
Clr
COMPF=0
COMPEN
SCON1.5(REGON)
EXIF.4
(COMPF)
Figure 6-10 The Configuration of Comparator
6.11 DTMF Generator
W925E/C625 provides a DTMF generator which outputs the dual tone multi-frequency signal to the
DTMF pin. The DTMF generator can work well at the operating frequency of 3.58MHz. A DTMF
generator register DTMFG controls the DTMF output and specifies the desired low/high frequency.
The tones are divided into two groups (low group and high group). When the generator is disable, the
DTMF pin is in tri-state. The relation between the DTMF signal and the corresponding touch tone
keypad is shown in Figure 6-11.
C1 C2 C3 C4
R1 _{1 2 3 A}
R2 _{4 5 6 B}
R3 _{7 8 9 C}
R4 _{* 0 # D}
Row/Col
R1
R2
R3
R4
C1
C2
C3
C4
Frequency
697 Hz
770 Hz
852 Hz
941 Hz
1209 Hz
1336 Hz
1477 Hz
1633 Hz
Figure 6-11 The Relation Between DTMF and Keypad
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Publication Release Date: July 4, 2005
Revision A10