TIR1000, TIR1000I

STANDALONE IrDA

™ ENCODER AND DECODER

SLLS228F – DECEMBER 1995 – REVISED JULY 1999

6

POST OFFICE BOX 655303

PRINCIPLES OF OPERATION

IrDA encoder function (continued)

The TIR1000 and TIR1000I can decode positive pulses on IR_RXD. The timing is different, but the variation

is invisible to the UART. The decoder, which works from the falling edge, now recognizes a zero on the trailing

edge of the pulse rather than on the leading edge. As long as the pulse width is fairly constant, as defined by

the specification, the trailing edges should also be 16 clock cycles apart and data can readily be decoded. The

zero appears on U_RXD after the pulse rather than at the start of it.

1

2

34567

8

10

12

14

16

IR_RXD

16XCLK

U_RXD

Figure 8. Positive IR_RXD Pulse Decode – Detailed View

16

Cycles

16

Cycles

16

Cycles

16

Cycles

16XCLK

IR_RXD

U_RXD

Figure 9. Positive IR_RXD Pulse Decode – Macro View