AN332
186
Confidential Rev. 0.2
10. Timing
There are two indicators: CTS (Clear to Send) and STC (Seek/Tune Complete) to indicate that a command has
been accepted and execution completed by the part.
After sending every command, the CTS bit will be set indicating that the command has been accepted by the part
and it is ready to receive the next command. The CTS bit, on most commands, also indicates that the command
has completed execution. These commands are:
1. POWER_UP, POWER_DOWN, GET_REV, GET_PROPERTY, GPIO_CTL, GPIO_SET
2. On FM Transmitter component: TX_TUNE_STATUS, TX_ASQ_STATUS, TX_RDS_BUFF, TX_RDS_PS
3. On FM Receive component: FM_TUNE_STATUS, FM_RSQ_STATUS, FM_RDS_STATUS
4. On AM/SW/LW Receive component: AM_TUNE_STATUS, AM_RSQ_STATUS
5. On WB Receive component: WB_TUNE_STATUS, WB_RSQ_STATUS, WB_ASQ_STATUS
The CTS timing model is shown in Figure 16 and the timing parameters for each command are shown in Table 41.
Figure 16. CTS Timing Model
In addition to CTS bit, there are a few commands (e.g. TX_TUNE_FREQ or FM_TUNE_FREQ) that use the STC
bit to indicate that the command has completed execution. It is highly recommended that user waits for the STC bit
before sending the next command. When interrupt is not used, user can poll the status of this STC bit by sending
the GET_INT_STATUS command until the STC bit has been set before sending the next command.
Commands that use STC bit to indicate execution has been completed:
1. On FM Transmitter component: TX_TUNE_FREQ, TX_TUNE_POWER, TX_TUNE_MEASURE
2. On FM Receive component: FM_TUNE_FREQ, FM_SEEK_START
3. On AM/SW/LW Receive component: AM_TUNE_FREQ, AM_SEEK_START
4. On WB Receive component: WB_TUNE_FREQ
The CTS and STC timing model is shown in Figure 17 and the timing parameters for each command are shown in
Table 41.
Control
Bus
COMMAND
GPO2/
INT
t
CTS
t
INT
