EZ80F91MCU ZILOG [Zilog, Inc.], EZ80F91MCU Datasheet - Page 224

• Manufacturer Part Number: EZ80F91MCU
• Description: eZ80Acclaim-TM Flash Microcontrollers
• Manufacturer: ZILOG [Zilog, Inc.]

Figure 37. Infrared Data Transmission
PS019209-0504
UART_TxD
Baud Rate
Transmit
Receive
IR_TxD
7-clock
Clock
delay
ble, but do not meet IrDA specifications. The UART must be enabled to use the
endec. Refer to the section covering the
mitter
tor.
The data to be transmitted via the IR transceiver is first data sent to UART0. The
UART transmit signal, TxD, and Baud Rate Clock are used by the endec to gener-
ate the modulation signal, IR_TxD, that drives the infrared transceiver. Each
UART bit is 16 clocks wide. If the data to be transmitted is a logical 1 (High), the
IR_TxD signal remains Low (0) for the full 16-clock period. If the data to be trans-
mitted is a logical 0, a 3-clock High (1) pulse is output following a 7-clock Low (0)
period. Following the 3-clock High pulse, a 6-clock Low pulse completes the full
16-clock data period. Data transmission is illustrated in Figure 37. During data
transmission, the IR receive function should be disabled by clearing the IR_RxEN
bit in the IR_CTL reg to 0 to prevent transmitter-to-receiver crosstalk.
Data received from the IR transceiver via the IR_RxD signal is decoded by the
endec and passed to the UART. The IR_RxEN bit in the IR_CTL register must be
set to enable the receiver decoder. The SIR data format uses half duplex commu-
nication. Therefore, the UART should not be allowed to transmit while the receiver
decoder is enabled. The UART Baud Rate Clock is used by the endec to generate
the demodulated signal, RxD, that drives the UART. Each UART bit is 16 clocks
wide. If the data to be received is a logical 1 (High), the IR_RxD signal remains
Start Bit = 0
on page 183 for more information on the UART and its Baud Rate Genera-
16-clock
period
3-clock
pulse
Data Bit 0 = 1
P R E L I M I N A R Y
Data Bit 1 = 0
Universal Asynchronous Receiver/Trans-
Data Bit 2 = 1
Product Specification
Infrared Encoder/Decoder
Data Bit 3 = 1
eZ80F91 MCU
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