SX1230 Просмотр технического описания (PDF) - Semtech Corporation

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SX1230

Integrated Transmitter IC Narrow/wideband 315 MHz, 434 MHz 868 MHz and 915 MHz band Transmitter

Semtech Corporation 

ADVANCED COMMUNICATIONS & SENSING

SX1230

Integrated Transmitter IC

DATASHEET

4. Working Modes of the SX1230

4.1. Operating Modes

The four operating modes of the SX1230 are shown in Table 6. Each of these may be selected via the SPI bus by writing

the corresponding bits to Mode(2:0). A key feature of the SX1230 is that the transition from one operating mode to the next

is automatically optimized. For example, if the transmit operating mode is selected whilst in sleep operating mode then, in

a pre-defined time-optimized sequence, each of the intermediate modes is engaged sequentially without the need to issue

any further SPI commands. For more information on timing and optimization please see Section 7.4.

Table 6 SX1230 Operating Modes

MODE(2:0)

000

001

010

011

Selected Mode

Sleep mode

Stand-by mode

FS mode

Transmit mode

RC Osc

Optional

Optional

Optional

Optional

Enabled Blocks

SPI

Xtal Osc Freq. Synth.

PA

x

x

x

x

x

x

x

x

x

x

4.2. Application Modes

The SX1230 has two application modes, selected by applying an external logical level to the E2_MODE input (pin 6). The

first, MCU mode (E2_Mode= ‘0’), configures the SX1230 as an SPI slave. This permits the configuration of the circuit by an

external microprocessor via the SPI interface of the SX1230 and the data to be applied via the DATA input (pin 14). The

second application mode, stand-alone mode (E2_Mode = 0), sees the SX1230 configured as SPI master. In the stand-

alone application mode the SX1230 can download its configuration from an external SPI E2PROM. Moreover, in response

to an input on the GPIO pins, a specific configuration can be programmed and a payload transmitted.

Note that this mode selection process is performed at start up (or POR) of the circuit. Thus the hardware mode cannot be

dynamically changed without resetting the chip. This may be achieved either by power down or by issuing an active high

POR signal to the Reset input (pin 5). For reset signal timing please see the diagram of Figure 13 and accompanying

description.

4.2.1. Stand Alone Mode

In stand alone mode (E2_Mode = ‘1’) the SX1230 will operate as a stand-alone SPI master which can download both

register settings and data payload from an SPI E2PROM. Four debounced GPIO inputs are available in stand alone mode,

in this application mode the SX1230 remains in sleep operating mode until either a single or combination of button presses

are detected. SX1230 can then be dynamically reconfigured and / or transmit a data sequence stored within the E2PROM.

The SX1230 can accommodate SPI E2PROM sizes up to 8 kbit and uses industry standard SPI commands. For a full

description of E2PROM use with SX1230 and the associated application circuits, please see Section 6.1. The application

circuit for stand-alone operation is shown in Figure 3, note that both matching and LM are band specific whilst CTX is

application specific.

SX1230, Revision 2 May 2009

©2008 Semtech Corp.

Page 10

www.semtech.com

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