Specifications

DATA SHEET QF4A512
Rev D4, Dec 07 27 www.quickfiltertech.com
10.3 Run Mode
By setting the run_mode bit to 1 the QF4A512 is in Run mode, and will output converted and filtered data.. A 24-bit format is used
including information and data (New Data Flag + Channel ID + 16 bits of data). The Serial Interface (SIF) will arbitrate between the
incoming channels from the FIRs by monitoring each channels internal data ready signal. If new data for a given channel is ready in
time, it will be inserted on the serial output stream at the appropriate spot for that channel and the new data flag will be set in the
header. Otherwise the old data will be output and the new data flag will not be set. The highest channel's sample rate will be used as
the data rate output for the DRDY signal, which can be used for handshaking to maximize bus throughput. Over and under range of the
ADC per channel can be monitored. See Section 10.4 for available commands in Run Mode.
The parity bit can be activated to verify proper data transfer. When turned on the parity bit will either add a 0 or 1 to force the remaining
23 bits to equal an odd number of 1's.
Note: For single-channel applications it is possible to use a “high-speed” 16-bit format, without the channel IDs and New Data Flag.
This would be used if bus throughput was the limiting item on overall performance. Use of this format is detailed in Application Note
QFAN002, “High-Speed Single Channel Operation”
.
Note: If the device is configured such that a low system clock is used in conjunction with the maximum SPI clock it may be possible for
/CS to return to a high level before DRDY has been cleared. To prevent this from occurring be sure to conform to the timing
requirements in Electrical Characteristics.
Figure 11. Run Mode Format
Table 9. Run Mode, Control Address for Command Writes, SDI (00h-FFh)
A7 A6 A5 A4 A3 A2 A1 A0
Addr7 Addr6 Addr5 Addr4 Addr3 Addr2 Addr1 Addr0
Addr7-Addr0 = Command Address
Description: See Section 10.4.
Table 10. Run Mode, Control Register Data Format (00h-FFh)
D7 D6 D5 D4 D3 D2 D1 D0
Data7 Data6 Data5 Data4 Data3 Data2 Data1 Data0
(Data7 - Data0) = Unique data per command.
Description: See Section 10.4.
Table 11. Run Mode, Output Data Structure, LSB, SD0 (0000h-FFFFh)
D7 D6 D5 D4 D3 D2 D1 D0
Data7 Data6 Data5 Data4 Data3 Data2 Data1 Data0
Data7- Data0 = Least Significant Byte (LSB)
Description: This is the Least Significant Byte of the 16-Bit filtered data output.
Table 12. Output Data, Second LSB, SD0 (0000h-FFFFh)
D15 D14 D13 D12 D11 D10 D9 D8
Data15 Data14 Data13 Data12 Data11 Data10 Data9 Data8
Data15- Data8 = Most Significant Byte (MSB)
Description: This is the Most Significant Byte of the 16-Bit filtered data output.
parity bit(1)
channel id(2)
Run Mode Format : Multi Channel (1 to 4) : 16 Effective # of Bits Output
ADC overflow/underflow
SO
SI
ch1 filter data(16 Bits)
ctrl write data(8)
ctrl address(8)
xxx
chN filter data(16 Bits)
x
xxx
x
ctrl write data(8)
ctrl address(8)
xxx
x
xxx
x
new data flag(1)
channel id(2)
new data flag(1)
parity bit(1) ADC overflow/underflow