AN543
Rev. 0.9
65
Command 0x36 FM_RDS_STATUS (Si4751/53/55/57 Only)
The FM_RDS_STATUS command returns RDS information for current channel and reads an entry from the RDS
FIFO. RDS information includes synch status, FIFO status, group data (blocks A, B, C, and D), and block errors
corrected. Maximum RDS FIFO size is 25 groups. This command clears the RDSINT interrupt bit when INTACK bit
in ARG1 is set, and, if MTFIFO is set, the entire RDS receive FIFO is cleared (FIFO is always cleared during
FM_TUNE_FREQ or FM_SEEK_START). The CTS bit (and optional interrupt) is set when it is safe to send the
next command. This command may only be sent in powerup mode.
Command
Bit
7
6
5
4
3
2
1
0
CMD
0x36
ARG1
00000
STATUS_ONLY
MTFIFO
INTACK
ARG
Bit
Name
Function
1
7:3
Reserved
Always write 00000.
1
2
STATUS_ONLY
Status Only.
Determines if data should be removed from the RDS FIFO.
0 = Data is removed from RDS FIFO, and RDSFIFOUSED decre-
ments by one. Data in BLOCKA, BLOCKB, BLOCKC, BLOCKD,
and BLE contain the oldest data in the RDS FIFO.
1 = Data is not removed from RDSFIFO, and the RDSFIFOUSED
value stays the same. Data in BLOCKA, BLOCKB, BLOCKC,
BLOCKD, BLE, PI, TP, PTY, and status contain the last valid data
received for the current station.
1
1
MTFIFO
Empty FIFO.
The FIFO will always be cleared during FM_TUNE_FREQ and
FM_SEEK_START
.
0 = If FIFO not empty, read and remove oldest FIFO entry.
1 = Clear RDS Receive FIFO.
1
0
INTACK
Interrupt Acknowledge.
0 = RDSINT status preserved.
1 = Clears RDSINT.
