Actel Fusion Mixed-Signal FPGAs
Direct Digital Input
The AV, AC, and AT pads can also be configured as high-voltage digital inputs (Figure 2-69). As
these pads are 12 V–tolerant, the digital input can also be up to 12 V. However, the frequency at
which these pads can operate is limited to 10 MHz.
To enable one of these analog input pads to operate as a digital input, its corresponding Digital
Input Enable (DENAxy) pin on the Analog Block must be pulled HIGH, where x is either V, C, or T
(for AV, AC, or AT pads, respectively) and y is in the range 0 to 9, corresponding to the appropriate
Analog Quad.
When the pad is configured as a digital input, the signal will come out of the Analog Block macro
on the appropriate DAxOUTy pin, where x represents the pad type (V for AV pad, C for AC pad, or
T for AT pad) and y represents the appropriate Analog Quad number. Example: If the AT pad in
Analog Quad 5 is configured as a digital input, it will come out on the DATOUT5 pin of the Analog
Block macro.
Off-Chip
AV
AC
AG
AT
Voltage
Monitor Block
Current
Monitor Block
Gate
Driver
Temperature
Monitor Block
Pads
On-Chip
Analog Quad
Prescaler
Prescaler
Prescaler
Power
MOSFET
Gate Driver
Digital
Input
Digital
Input
Digital
Input
Current
Monitor / Instr
Amplifier
Temperature
Monitor
To FPGA
(DAVOUTx)
To FPGA
(DACOUTx)
From FPGA
(GDONx)
To FPGA
(DATOUTx)
To Analog MUX
To Analog MUX
To Analog MUX
Figure 2-69 • Analog Quad Direct Digital Input Configuration
Preliminary v1.7
2-89
ACTEL [ Actel Corporation ]
