Silicon Laboratories Si4704 Series Programming Manual page 10

AN332
5.1.1. Commands and Properties for the FM/RDS Transmitter
Command 0x01. POWER_UP
Initiates the boot process to move the device from powerdown to powerup mode. The boot can occur from internal
device memory or a system controller downloaded patch. To confirm that the patch is compatible with the internal
device library revision, the library revision should be confirmed by issuing the POWER_UP command with
Function = 15 (query library ID). The device will return the response, including the library revision, and then moves
into powerdown mode. The device can then be placed in powerup mode by issuing the POWER_UP command
with Function = 2 (transmit) and the patch may be applied. Only the STATUS byte will be returned in the response
stream in transmit mode. The POWER_UP command configures the state of DIN (pin 13), DFS (pin 14), and RIN
(pin 15) and LIN (pin 16) for analog or digital audio modes and GPO2/INT (pin 18) for interrupt operation. The
command configures GPO2/INT interrupts (GPO2OEN) and CTS interrupts (CTSIEN). If both are enabled,
GPO2/INT is driven high during normal operation and low for a minimum of 1 µs during the interrupt. The CTSIEN
bit is duplicated in the GPO_IEN property. The command is complete when the CTS bit (and optional interrupt) is
set.
Note: To change function (e.g., FM TX to FM RX), issue the POWER_DOWN command to stop the current function; then,
issue POWER_UP to start the new function.
Command Arguments: Two
Response Bytes: None (FUNC = 2), Seven (FUNC = 15)
Command
Bit D7
CMD
0
ARG1
CTSIEN
ARG2
ARG Bit Name
1 7 CTSIEN
1 6 GPO2OEN
1 5 PATCH
1 4 XOSCEN
10
D6 D5
0 0
GPO2OEN PATCH XOSCEN
CTS Interrupt Enable.
0 = CTS interrupt disabled.
1 = CTS interrupt enabled.
GPO2 Output Enable.
0 = GPO2 output disabled, (Hi-Z).
1 = GPO2 output enabled.
Patch Enable.
0 = Boot normally
1 = Copy non-volatile memory to RAM, but do not boot. After CTS has been set,
RAM may be patched
Crystal Oscillator Enable.
0 = Use external RCLK (crystal oscillator disabled).
1 = Use crystal oscillator (RCLK and GPO3/DCLK with external 32.768 kHz crys-
tal and OPMODE=00000101).
See Si47xx Data Sheet Application Schematic for external BOM details.
Confidential Rev. 0.2
D4 D3 D2
0 0 0
OPMODE[7:0]
Function
D1 D0
0 1
FUNC[3:0]