MAXQ61HX-0000+ MAXIM [Maxim Integrated Products], MAXQ61HX-0000+ Datasheet - Page 13

• Manufacturer Part Number: MAXQ61HX-0000+
• Description: 16-BIt Microcontroller with Infrared Module
• Manufacturer: MAXIM [Maxim Integrated Products]

Figure 3. IR Transmission Waveform (IRCFME = 0)
The normal transmit mode modulates the carrier based
upon the IRDATA bit. However, the user has the option
to input the modulator (envelope) on an external pin if
desired. If the IRENV[1:0] bits are configured to 01b or
10b, the modulator/envelope is output to the IRTXM pin.
The IRDATA bit is output directly to the IRTXM pin (if
IRTXPOL = 0) on each IRV downcount interval bound-
ary just as if it were being used to internally modulate
the carrier frequency. If IRTXPOL = 1, the inverse of the
IRDATA bit is output to the IRTXM pin on the IRV inter-
val downcount boundaries. The envelope output is illus-
trated in Figure 4. When the envelope mode is enabled,
it is possible to output either the modulated (IRENV[1:0]
= 01b) or unmodulated (IRENV[1:0] = 10b) carrier to
the IRTX pin.
When configured in receive mode (IRMODE = 0), the IR
hardware supports the IRRX capture function. The
IRRXSEL[1:0] bits define which edge(s) of the IRRX pin
should trigger IR timer capture function.
The IR module starts operating in the receive mode
when IRMODE = 0 and IREN = 1. Once started, the IR
timer (IRV) starts up counting from 0000h when a quali-
IR Transmit—Independent External Carrier
CARRIER OUTPUT
IR INTERRUPT
IRTXPOL = 1
IRTXPOL = 0
IRDATA
16-Bit Microcontroller with Infrared Module
(IRV)
IRTX
IRTX
0
IRMT = 3
3
______________________________________________________________________________________
1
2
and Modulator Outputs
1
0
3
2
IR Receive
1
0
0
fied capture event as defined by IRRXSEL happens.
The IRV register is, by default, counting carrier cycles
as defined by the IRCA register. However, the IR carrier
frequency detect (IRCFME) bit can be set to 1 to allow
clocking of the IRV register directly with the IRCLK for
finer resolution. When IRCFME = 0, the IRCA defined
carrier is counted by IRV. When IRCFME = 1, the
IRCLK clocks the IRV register.
On the next qualified event, the IR module does the
following:
1) Captures the IRRX pin state and transfers its value to
2) Transfers its current IRV value to the IRMT.
3) Resets IRV content to 0000h (if IRXRL = 1).
4) Continues counting again until the next qualified
If the IR timer value rolls over from 0FFFFh to 0000h
before a qualified event happens, the IR timer overflow
(IROV) flag is set to 1 and an interrupt generated if
enabled. The IR module continues to operate in receive
mode until it is stopped by switching into transmit mode
(IRMODE = 1) or clearing IREN = 0.
IRDATA. If a falling edge occurs, IRDATA = 0. If a
rising edge occurs, IRDATA = 1.
event.
13