ez80f92 ZiLOG Semiconductor, ez80f92 Datasheet - Page 135

• Manufacturer Part Number: ez80f92
• Description: Ez80acclaim Flash Microcontrollers
• Manufacturer: ZiLOG Semiconductor

Table 69. GPIO Mode Selection when using the IrDA Encoder/Decoder
PS015313-0508
GPIO Port D Bits
PD0
PD1
PD2–PD7
Jitter
Infrared Encoder/Decoder Signal Pins
Loopback Testing
Setting the upper 4 bits of IR_CTL to
receiver. In this mode, the IrDA receiver uses edge detection on the IR_RxD bit stream.
Due to the inherent sampling of the received IR_RxD signal by the BIt Rate Clock, some
jitter can be expected on the first bit in any sequence of data. However, all subsequent bits
in the received data stream are a fixed 16 clock periods wide.
The IrDA endec signal pins (IR_TxD and IR_RxD) are multiplexed with General-Purpose
I/O (GPIO) pins. These GPIO pins must be configured for alternate function operation for
the endec to operate.
The remaining six UART0 pins (CTS0, DCD0, DSR0, DTR0, RTS and RI0) are not
required for use with the endec. The UART0 modem status interrupt should be disabled to
prevent unwanted interrupts from these pins. The GPIO pins corresponding to these six
unused UART0 pins can be used for inputs, outputs, or interrupt sources. Recommended
GPIO Port D control register settings are provided in
Input/Output on page 39 for additional information about setting the GPIO Port modes.
Both internal and external loopback testing can be accomplished with the IrDA endec on
the eZ80F92 device. Setting the LOOP_BACK bit to 1 enables internal loopback testing.
During internal loopback, the IR_TxD output signal is inverted and connected on-chip to
the IR_RxD input. External loopback testing of the off-chip IrDA transceiver can be
accomplished by transmitting data from the UART while the receiver is enabled
(IR_RxEN set to 1).
Allowable GPIO
Port Mode
7
7
Any other than GPIO Mode 7
(1, 2, 3, 4, 5, 6, 8, or 9)
00h
Alternate function.
Alternate function.
Allowable Port Mode Functions
Output, input, open-drain, open-source, level-
sensitive interrupt input, or edge-triggered
interrupt input.
disables the frequency divider but not the IrDA
Table
69. See General-Purpose
Product Specification
Infrared Encoder/Decoder
128