SPIRIT1 datasheet(69/94 Pages) STMICROELECTRONICS

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SPIRIT1

MCU interface

Doc ID 022758 Rev 3

69/94

using the IRQ_MASK[3:0] registers: if the mask bit related to a particular event is

programmed at 0, that event does not generate any interrupt request.

10.3

GPIOs

The total number of GPIO pins is 4. Each pin is individually configurable.

Digital outputs can be selected from the following (see GPIOx_CONF register):

Table 33.

Digital outputs

I/O

selection

Output signal

nIRQ (interrupt request, active low)

POR inverted (active low)

Wake-up timer expiration: ‘1’ when WUT has expired

Low battery detection: ‘1’ when battery is below threshold setting

TX data internal clock output (TX data are sampled on the rising edge of it)

TX state indication: ‘1’ when the SPIRIT1 is transiting in the TX state

TX FIFO almost empty flag

TX FIFO almost full flag

RX data output

RX clock output (recovered from received data)

RX state indication: ‘1’ when SPIRIT1 is transiting in the RX state

RX FIFO almost full flag

RX FIFO almost empty flag

Antenna switch used for antenna diversity

Valid preamble detected flag

Sync word detected flag

RSSI above threshold (same indication as bit CS in the LINK_QUALIF[1]

MCU clock

TX or RX mode indicator (to enable an external range extender)

VDD (to emulate an additional GPIO of the MCU, programmable by SPI)

GND (to emulate an additional GPIO of the MCU, programmable by SPI)

External SMPS enable signal (active high)

Device in SLEEP or STANDBY states

Device in READY state

Device in LOCK state

Device waiting for a high level of the lock-detector output signal

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