Datasheet

 
      
    
SLAS251A − DECEMBER 1999 − REVISED JANUARY 2003
6
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
control and timing
power up and initialization requirements
D Determine processor type by writing A000h to the TLV1504/48 (CS must be toggled)
D Configure the device (CS must make a high-to-low transition, then can be held low if in DSP mode; i.e.,
active FS.)
The first conversion after power up or resuming from power down is not valid.
start of the cycle:
D When FS is not used (FS = 1 at the falling edge of CS), the falling edge of CS is the start of the cycle.
D When FS is used (FS is an active signal from a DSP), the falling edge of FS is the start of the cycle.
first 4-MSBs: the command register (CMR)
The TLV1504/TLV1508 have a 4-bit command set (see Table 1) plus a 12-bit configuration data field. Most of
the commands require only the first 4 MSBs, i.e., without the 12-bit data field.
The valid commands are listed in Table 1.
Table 1. TLV1504/TLV1508 Command Set
SDI D(15−12) BINARY TLV1508 COMMAND TLV1504 COMMAND
0000b 0h Select analog input channel 0 Select analog input channel 0
0001b 1h Select analog input channel 1 N/A
0010b 2h Select analog input channel 2 Select analog input channel 1
0011b 3h Select analog input channel 3 N/A
0100b 4h Select analog input channel 4 Select analog input channel 2
0101b 5h Select analog input channel 5 N/A
0110b 6h Select analog input channel 6 Select analog input channel 3
0111b 7h Select analog input channel 7 N/A
1000b 8h SW power down (analog + reference)
1001b 9h Read CFR register data shown as SDO D(11−0)
1010b Ah plus data
Write CFR followed by 12-bit data, e.g., 0A100h means external reference,
short sampling, SCLK/4, single shot, INT
1011b Bh Select test, voltage = (REFP+REFM)/2
1100b Ch Select test, voltage = REFM
1101b Dh Select test, voltage = REFP
1110b Eh FIFO read, FIFO contents shown as SDO D(15−4), D(3−0) = 0000
1111b
Fh plus data
Reserved
1111b Fh plus data Reserved
NOTE: The status of the CFR can be read with a read CFR command when the device is programmed
for one-shot conversion mode (CFR D[6,5] = 00).