Z8F082ASJ020EG Datasheet, PDF (138/282 Pages) Zilog, Inc. – High-Performance 8-Bit Microcontrollers

Z8 Encore! XP^® F082A Series
Product Specification
121
The baud rate is set by the UART’s Baud Rate Generator and supports IrDA standard baud
rates from 9600 baud to 115.2 kbaud. Higher baud rates are possible, but do not meet IrDA
specifications. The UART must be enabled to use the infrared endec. The infrared endec
data rate is calculated using the following equation:
Infrared Data Rate (bits/s)
=
--------^S---^y---^s--^t--^e--^m------^C----^l-^o---^c--^k----^F---^r--^e--^q---^u---^e---ⁿ---^c--^y----⁽--^H---^z---⁾-------
16  UART Baud Rate Divisor Value
Transmitting IrDA Data
The data to be transmitted using the infrared transceiver is first sent to the UART. The
UART’s transmit signal (TXD) and baud rate clock are used by the IrDA to generate the
modulation signal (IR_TXD) that drives the infrared transceiver. Each UART/Infrared
data bit is 16 clocks wide. If the data to be transmitted is 1, the IR_TXD signal remains
low for the full 16 clock period. If the data to be transmitted is 0, the transmitter first out-
puts a 7 clock low period, followed by a 3 clock high pulse. Finally, a 6 clock low pulse is
output to complete the full 16 clock data period. Figure 17 displays IrDA data transmis-
sion. When the infrared endec is enabled, the UART’s TXD signal is internal to the Z8
Encore! XP F082A Series products while the IR_TXD signal is output through the TXD
pin.
Baud Rate
Clock
16 clock
period
UART’s
TXD
IR_TXD
Start Bit = 0
3 clock
pulse
Data Bit 0 = 1
Data Bit 1 = 0
Data Bit 2 = 1
Data Bit 3 = 1
7-clock
delay
Figure 17. Infrared Data Transmission
PS022827-1212
PRELIMINARY
Operation