Maxim-integrated MAXQ622 Bedienungsanleitung PDF herunterladen (Seite 129)

MAXQ612/MAXQ622 User’s Guide

Maxim Integrated 8-5

8.4 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 qualified capture event as defined by IRRXSEL happens. The IRV register will,

by default, be counting carrier cycles as defined by the IRCA register. However, the IR clock frequency mux enable

(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.

Figure 8-4. External IRTXM (Modulator) Output

Figure 8-5. IR Capture

0 0 0 01 1 1 1

IRDATA

IRMT IRMT IRMT IRMT

IR INTERRUPT

IRV INTERVAL

IRTXM

(IRTXPOL = 1)

IRTXM

(IRTXPOL = 0)

IRCAH + 1

IRCFME

RESER IRV TO 0000h

IRXRL

IRCAL + 1

CARRIER GENERATION

EDGE DETECT

CARRIER MODULATION

IR TIMER OVERFLOW

IR INTERRUPT

INTERRUPT TO CPU

IRDATA

COPY IRV TO IRMT

ON EDGE DETECT

0000h IRV

IRCLK

IRRX PIN

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Maxim-integrated MAXQ622 Bedienungsanleitung Seite 129