dimtel
dimtel
9.5
AD8842 8-channel DAC
Table 13 – continued from previous page
Address
Bits
Definition
0x000125
11:0
ADC channel 5
0x000126
11:0
ADC channel 6
0x000127
11:0
ADC channel 7
9.5
AD8842 8-channel DAC
iGp-5120F includes 8-channel 8-bit serial-interface DAC. The SPI controller
for the DAC uses 8 consecutive addresses, as shown in Table 14. Writing to
one of the registers starts an SPI writing cycle which loads the new value
into the DAC. On writes only the 8 LSB are used. Register reads are sign-
extended to 16 bits. DAC reference voltage is 3 V for
−
3 to +3 V output
range. Output drivers generate full swing into high-impedance loads. For
50 Ω loads the swing is reduced to 1 V.
Unlike other DAC channels, channel 7 is not brought out to the front-
panel connector. Its output is used to trim the DC level of the high-speed
DAC. The output is attenuated to produce
±
5 % of full-scale adjustment of
the DC level.
Table 14: FPGA registers: AD8842 DAC
Address
Bits
Definition
0x000128
7:0
DAC channel 0
0x000129
7:0
DAC channel 1
0x00012a
7:0
DAC channel 2
0x00012b
7:0
DAC channel 3
0x00012c
7:0
DAC channel 4
0x00012d
7:0
DAC channel 5
0x00012e
7:0
DAC channel 6
0x00012f
7:0
DAC channel 7
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