DAC34SH84_15 Datasheet, PDF (44/93 Pages) Texas Instruments – DAC34SH84 Quad-Channel, 16-Bit, 1.5 GSPS Digital-to-Analog Converter (DAC)

DAC34SH84
SLAS808E – FEBRUARY 2012 – REVISED SEPTEMBER 2015
www.ti.com
In this mode the ISTR signal functions as a parity signal and cannot be used to sync the FIFO pointer
simultaneously. It is recommended to use the SYNC to sync the FIFO pointer. If ISTR has to be used to sync the
FIFO pointer, the ISTR sync can only be possible upon start-up when dual 16-bit parity function is disabled.
Once the initialization is finished, disable the FIFO pointer sync through ISTR (by configuring syncsel_fifoin and
syncsel_fifoout in config32) and enable the dual 16-bit parity function afterwards.
ISTR
DAB[15:0]
Parity Block
oddeven_parity
alarm_Aparity
alarm_Bparity
DATACLK
PARITY
DCD[15:0]
Parity Block
oddeven_parity
alarm_Cparity
alarm_Dparity
DATACLK
Figure 76. DAC34SH84 Dual 16-Bit Parity Check
B0463-01
7.3.13 DAC34SH84 Alarm Monitoring
The DAC34SH84 includes a flexible set of alarm monitoring that can be used to alert of a possible malfunction
scenario. All the alarm events can be accessed either through the config5 register or through the ALARM pin.
Once an alarm is set, the corresponding alarm bit in register config5 must be reset through the serial interface to
allow further testing. The set of alarms includes the following conditions:
Zero check alarm
• Alarm_from_zerochk. Occurs when the FIFO write pointer has an all zeros pattern. Since the write pointer is a
shift register, all zeros will cause the input point to be stuck until the next sync event. When this happens a
sync to the FIFO block is required.
FIFO alarms
• alarm_from_fifo. Occurs when there is a collision in the FIFO pointers or a collision event is close.
– alarm_fifo_2away. Pointers are within two addresses of each other.
– alarm_fifo_1away. Pointers are within one address of each other.
– alarm_fifo_collision. Pointers are equal to each other.
Clock alarms
• clock_gone. Occurs when either the DACCLK or DATACLOCK have been stopped.
– alarm_dacclk_gone. Occurs when the DACCLK has been stopped.
– alarm_dataclk_gone. Occurs when the DATACLK has been stopped.
Pattern checker alarm
• alarm_from_iotest. Occurs when the input data pattern does not match the pattern key.
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