UPSD3422_06 Datasheet, PDF (113/293 Pages) STMicroelectronics – Turbo Plus Series Fast Turbo 8032 MCU with USB and Programmable Logic

uPSD34xx
IrDA interface
Table 51.
Bit
7:4
3:2
1:0
Baud rate selection register (SFR xxh, reset value xxh)
Symbol
R/W
Definition
BR[3:0]
R,W Specify Baud Rate (see Table 52)
PULSE
IrDA Pulse Modulation Select
R,W 0 = 3/16 bit time pulses (not recommended)
1 = 1.627µs
IRDAEN
0 = IrDA Interface is disabled
R,W 1 = IrDA is enabled, UART#1 outputs are disconnected from
Port 1 (or Port 4)
Table 52. Baud rate of UART#1 for IrDA interface
BR3
BR2
BR1
BR0
Baud Rate (kbps)
0
0
0
0
115.2
0
0
0
1
57.5
0
0
1
0
38.4
0
0
1
1
19.2
0
1
0
0
14.4
0
1
0
1
12.8
0
1
1
0
9.6
0
1
1
1
7.2
1
0
0
0
4.8
1
0
0
1
3.6
1
0
1
0
2.4
1
0
1
1
1.8
1
1
0
0
1.2
22.2
Pulse width selection
The IrDA interface has two ways to modulate the standard UART1 serial stream:
1. An IrDA data pulse will have a constant pulse width for any bit time, regardless of the
selected baud rate.
2. An IrDA data pulse will have a pulse width that is proportional to the the bit time of the
selected baud rate. In this case, an IrDA data pulse width is 3/16 of its bit time, as
shown in Figure 40 on page 111.
The PULSE bit in the SFR named IRDACON determines which method above will be used.
According to the IrDA physical layer specification, for all baud rates at 115.2k bps and below,
the minimum data pulse width is 1.41µs. For a baud rate of 115.2k bps, the maximum pulse
width 2.23µs. If a constant pulse width is to be used for all baud rates (PULSE bit = 0), the
ideal general pulse width is 1.63µs, derived from the bit time of the fastest baud rate (8.68µs
bit time for 115.2k bps rate), multiplied by the proportion, 3/16.
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