Z8F4822AR020SG Datasheet, PDF (130/323 Pages) Zilog, Inc. – High Performance 8-Bit Microcontrollers

Z8 Encore! XP^® F64xx Series
Product Specification
110
passed to the UART. Communication is half-duplex, which means simultaneous data
transmission and reception is not allowed.
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-clock 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, a 3-clock high pulse is output
following a 7-clock low period. After the 3-clock high pulse, a 6-clock low pulse is output
to complete the full 16-clock data period. Figure 20 displays IrDA data transmission.
When the infrared endec is enabled, the UART’s TxD signal is internal to the Z8 Encore!
XP F64xx 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 20. Infrared Data Transmission
PS019924-0113
PRELIMINARY
Operation