Enabling Infrared (Ir) Modes; Uart2 Package Dependency; Clocking Requirements; Table 15-1. Uart2 / Irda Modes - Cirrus Logic EP93 Series User Manual

15.2.4 Enabling Infrared (Ir) Modes

Mode
Disabled
UART2
SIR
MIR
FIR

15.3 UART2 Package Dependency

UART2 uses package pins RXD1 and TXD1. Pin RXD1 drives both the UART2 UART input
and the UART2 SIR input.
However, Syscon register DeviceCfg[28] (IonU2) controls what drives pin TXD1. See
Table 15-2.
IonU2
Therefore, to use any IrDA mode, FIR, MIR or SIR, set IonU2. To use UART2 as a UART,
clear IonU2.

15.3.1 Clocking Requirements

There are two clocks, PCLK and UARTCLK.
UARTCLK frequency must accommodate the desired range of baud rates:
The frequency of UARTCLK must also be within the required error limits for all baud rates to
be used.
To allow sufficient time to write the received data to the receive FIFO, UARTCLK must be less
than or equal to four times the frequency of PCLK:
DS785UM1

Table 15-1. UART2 / IrDA Modes

DeviceCfg Register
U2EN IonU2
0 x
1 0
1 1
x 1
x 1

Table 15-2. IonU2 Pin Function

0 UART2 UART is the output signal
1 Logical OR of IrDA output signal and UART2 SIR output signal
Fuartclk(min) >= 32 x baud_rate(max)
Fuartclk(max) <= 32 x 65,536 x baud_rate(min)
Copyright 2007 Cirrus Logic
UART2Ctrl Register
SirEn UARTE
0 0
0 1
1 1
0 0
0 0
Pin TXD1 Function
UART2
EP93xx User's Guide
IrEnable Register
EN[1] EN[0]
0 0
0 0
0 1
1 0
1 1
15
15-5