Epson S1C17M20 Technical Manual page 221

17 IR REMOTE CONTROLLER (REMC3)
Carrier signal
Data signal (Modulated data)
REMO output
REMCCTL. REMDBCTL.
OUTINVEN bit REMOINV bit
0
0
1
1
Carrier signal
The carrier signal is generated by comparing the values of the 8-bit counter for carrier generation that runs with
CLK_REMC3 and the setting values of the REMCARR.CRDTY[7:0] and REMCARR.CRPER[7:0] bits. Fig-
ure 17.4.3.2 shows an example of the carrier signal generated.
Example) REMCARR.CRDTY[7:0] bits = 2, REMCARR.CRPER[7:0] bits = 8
CLK_REMC3
8-bit counter for
carrier generation
Carrier signal
The carrier signal frequency and duty ratio can be calculated by the equations shown below.
Carrier frequency = ——————
Where
f : CLK_REMC3 frequency [Hz]
CLK_REMC3
CRPER: REMCARR.CRPER[7:0] bit-setting value (1–255)
CRDTY: REMCARR.CRDTY[7:0] bit-setting value (0–254)
* REMCARR.CRDTY[7:0] bits < REMCARR.CRPER[7:0] bits
The 8-bit counter for carrier generation is reset by the REMDBCTL.PRESET bit and is started/stopped by the
REMDBCTL.PRUN bit in conjunction with the 16-bit counter for data signal generation. When the counter
value is matched with the REMCARR.CRDTY[7:0] bits, the carrier signal waveform is inverted. When the
counter value is matched with the REMCARR.CRPER[7:0] bits, the carrier signal waveform is inverted and the
counter is reset to 0x00.
Data signal
The data signal is generated by comparing the values of the 16-bit counter for data signal generation (REM-
DBCNT.DBCNT[15:0] bits) that runs with CLK_REMC3 and the setting values of the REMAPLEN.
APLEN[15:0] and REMDBLEN.DBLEN[15:0] bits. Figure 17.4.3.3 shows an example of the data signal gen-
erated.
17-4
0
1
0
1
Figure 17.4.3.1 REMO Output Waveform Example
0 1 2 3 4 5 6 7 8 0 1 2 3 4 5 6 7 8 0 1 2 3 4
Figure 17.4.3.2 Example of Carrier Signal Generated
f
CLK_REMC3
Duty ratio = ——————
CRPER + 1
Seiko Epson Corporation
Data bit
A
B
A: REMCARR.CRDTY[7:0] bits + 1 [clock]
B: REMCARR.CRPER[7:0] bits + 1 [clock]
CRDTY + 1
CRPER + 1
(Eq. 17.1)
S1C17M20/M21/M22/M23/M24/M25
TECHNICAL MANUAL (Rev. 1.0)