
MAXQ610
16-Bit Microcontroller with Infrared Module
16
______________________________________________________________________________________
0
1
0000h
IRV
CARRIER MODULATION
CARRIER GENERATION
IRCLK
IRCFME
IRCAL + 1
IRCAH + 1
INTERRUPT TO CPU
IRDATA
IRRX PIN
RESET IRV TO 0000h
IR TIMER OVERFLOW
IR INTERRUPT
IRXRL
COPY IRV TO IRMT
ON EDGE DETECT
EDGE DETECT
Figure 5. IR Capture
IRDATA
IR INTERRUPT
IRV INTERVAL
IRTXM
IRTXPOL = 1
IRTXM
IRTXPOL = 0
IRMT
01
0
1
0
10
1
Figure 4. External IRTXM (Modulator) Output
IR Receive
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-
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.