AN230 Datasheet, PDF (14/42 Pages) Silicon Laboratories – Device initialization sequence and busmode selection

AN230
3.2.4. GPIO1 (04h.1:0)—General Purpose I/O 1
GPIO1 can be programmed to 3 different states as shown in Table 5. This pin can be used to control an LED,
another device in the system, or left unused.
Table 5. GPIO1 States
00 High impedance (default)
01 Reserved
10 Low output (GND level)
11 High output (V_IO level)
3.2.5. GPIO2 (04h.3:2)/RDSIEN (04h.15)/STCIEN (04h.14)—General Purpose I/O 2, Interrupts
GPIO2 can be programmed to 4 different states as shown in Table 6. When programmed as an interrupt, the
Si470x device will generate interrupts based on the settings of RDSIEN and STCIEN. If RDSIEN is set a 5 ms
interrupt pulse will be generated when RDS data is available. If STCIEN is set a 5 ms interrupt pulse will be
generated upon completion of a SEEK or TUNE command. If both interrupts are enabled, the first interrupt after a
SEEK or TUNE will be the STC interrupt. Subsequent interrupts will be RDS interrupts. This pin can also be used
as a general purpose output or left unused. RDS is only available on the Si4701 and Si4703.
Table 6. GPIO2 States
00 High impedance (default)
01 STC/RDS interrupt
10 Low output (GND level)
11 High output (V_IO level)
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