Installation Manual

IRIS OEM Edition Hardware Reference Manual
Baud Rate
(bps)
U2X = 0
UBRR
U2X = 0
ERROR
U2X = 1
UBRR
U2X = 1
ERROR
2400 191 0.0% 383 0.0%
4800 95 0.0% 191 0.0%
9600 47 0.0% 95 0.0%
14.4k 31 0.0% 63 0.0%
19.2k 23 0.0% 47 0.0%
28.8k 15 0.0% 31 0.0%
38.4k 11 0.0% 23 0.0%
57.6k 7 0.0% 15 0.0%
76.8k 5 0.0% 11 0.0%
115.2k 3 0.0% 7 0.0%
4.5.2 UART1
USART1 is a shared interface, used for communication with the on-board serial flash, as well as
external serial peripherals. Proper management of the chip select lines (FLASH_CS) is required
to avoid port contention. The serial flash also has a reset line (FLASH_RSTN) that can be
asserted externally to place the serial flash in a known state. The flash reset line has an internal
10K pull-up resistor to enable the device after power-on. Additional pull-up resistors may be
required on the USART1_TX, USART1_RX, and USART_CK lines to avoid unintentional
communication with external peripherals during reset or power-on.
4.5.3 I2C
The I2C bus is a two-wire interface that is meant to control I2C peripherals. I2C peripherals
usually require an external 5K pull-up to supply power to the port, and use an addressing scheme
that is internal to the I2C peripheral. Many of the I2C peripherals have an internal hard-wired
portion of their address along with some external address decode lines in the event multiple
devices of the same kind are attached to the bus. See the individual vendor datasheets for details.
4.5.4 SPI
The SPI bus is a bidirectional synchronous bus common to many devices available. As it is
applied in the OEM Edition module, the SPI bus is dedicated to the radio data interface, and
cannot be used for other peripherals. The SPI_CK line is made available to facilitate
reprogramming the processor, and should be left in a high impedance state when not in
programming mode.
4.5.5 One-Wire
The One-Wire bus is a single wire bidirectional bus used to communicate with the Dallas/Maxim
series of One-Wire peripherals. These devices require a 5k resistor to VCC to bias the pin, and
accurate timing of signals on the bus for proper communication.
WARNING: The choice of system clock is critical to making this interface work.
4.5.6 ADC Ports
The OEM Edition module features 10-bit successive approximation ADC. The ADC is
connected to an 8-channel Analog Multiplexer which allows 8 single-ended voltage inputs. The
Page 20 Doc. # 7430-0549-01 Rev. B