Lucent Technologies MN102F75K User Manual

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The IR remote signal receiver has three operating modes: HEAMA, 5-/6-bit, and 

HEAMA–5-/6-bit automatic detect. Set the mode in the MODAUTO and 
MODSEL bits of the interrupt control register, RMIR. The FMTMON bit of the 

interrupt status register, RMIS, monitors the operating mode.

In automatic detect mode, the microcontroller checks the interval between 

remote signal edges. If the interval is (n - 4T

S

) to (n + 3T

S

), where n is the leader 

value set in the LD[3:0] field of the RMLD register, it processes the data in 

HEAMA format. If the interval is 28 to 35 T

S

 cycles, it processes the data in 

5-/6-bit format.

The IR remote signal receiver contains a noise filter to eliminate noise from the 

remote signal. To enable the noise filter, set the FILTRE bit of the interrupt 
control register, RMIR, to 1. The noise filter samples the remote input signal 

every PWM6 cycle (21.3 µs) or PWM8 cycle (85.5 µs), then outputs the value 
that it sampled at least three times during the last four sampling cycles. This 

eliminates any noise occurring during one or two sampling cycles. Select the 
sampling clock (PWM6 or PWM8) with the SP bit of the RMLD register. 

(PWM6 is selected at reset.)

Sampling

Noise filter

output

Noise eliminated

Remote signal