M1AFS600-PQ208 Datasheet, PDF (124/334 Pages) Microsemi Corporation – Fusion Family of Mixed Signal FPGAs

Device Architecture
ADC Input Multiplexer
At the input to the Fusion ADC is a 32:1 multiplexer. Of the 32 input channels, up to 30 are user
definable. Two of these channels are hardwired internally. Channel 31 connects to an internal
temperature diode so the temperature of the Fusion device itself can be monitored. Channel 0 is wired to
the FPGA’s 1.5 V VCC supply, enabling the Fusion device to monitor its own power supply. Doing this
internally makes it unnecessary to use an analog I/O to support these functions. The balance of the MUX
inputs are connected to Analog Quads (see the "Analog Quad" section on page 2-83). Table 2-40 defines
which Analog Quad inputs are associated with which specific analog MUX channels. The number of
Analog Quads present is device-dependent; refer to the family list in the "Fusion Family" table on page I
of this datasheet for the number of quads per device. Regardless of the number of quads populated in a
device, the internal connections to both VCC and the internal temperature diode remain on Channels 0
and 31, respectively. To sample the internal temperature monitor, it must be strobed (similar to the AT
pads). The TMSTBINT pin on the Analog Block macro is the control for strobing the internal temperature
measurement diode.
To determine which channel is selected for conversion, there is a five-pin interface on the Analog Block,
CHNUMBER[4:0], defined in Table 2-39.
Table 2-39 • Channel Selection
Channel Number
0
1
2
3
.
.
.
30
31
CHNUMBER[4:0]
00000
00001
00010
00011
.
.
.
11110
11111
Table 2-40 shows the correlation between the analog MUX input channels and the analog input pins.
Table 2-40 • Analog MUX Channels
Analog MUX Channel
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Signal
Vcc_analog
AV0
AC0
AT0
AV1
AC1
AT1
AV2
AC2
AT2
AV3
AC3
AT3
AV4
AC4
AT4
Analog Quad Number
Analog Quad 0
Analog Quad 1
Analog Quad 2
Analog Quad 3
Analog Quad 4
2-108
Revision 4