
Hercules III User Manual Rev A.2
www.diamondsystems.com
Page
71
AINTE
Base+4,
bit 0
SCANE
Base+2,
bit 1
Operation
0
0
Single A/D conversions are triggered by write to B+0.
STS stays high during the A/D conversion.
No interrupt occurs.
The user program monitors STS (Base+3, bit 7) and reads A/D data when STS
goes low.
0
1
A/D scans are triggered by write to B+0. All channels between LOW and HIGH
are sampled.
STS stays high during the entire scan (multiple A/D conversions).
No interrupt occurs.
The user program monitors STS (Base+3, bit 7) and reads A/D data when STS
goes low.
1
0
Single A/D conversions are triggered by the source selected with ADCLK
(Base+4, bit 4).
STS stays high during the A/D conversion.
A/D interrupt occurs when the FIFO reaches its programmed threshold.
The interrupt routine reads the number of samples equal to the FIFO threshold
(Base+5, bits 0-5).
1
1
A/D scans are triggered by the source selected with ADCLK (Base+4, bit 4).
STS stays high during the entire scan (multiple A/D conversions).
A/D interrupt occurs when the FIFO reaches its programmed threshold.
The interrupt routine reads the number of samples equal to the FIFO threshold
(Base+5, bits 0-5).
16. DIGITAL-TO-ANALOG OUTPUT RANGES AND RESOLUTION
16.1
Description
Hercules III uses a 4-channel 12-bit D/A converter (DAC) to provide four analog outputs. A 12-bit DAC can
generate output voltages with the precision of a 12-bit binary number. The maximum value of a 12-bit binary
number is 2
12
- 1, or 4095, so the full range of numerical values that the DACs support is 0 - 4095. The value 0
always corresponds to the lowest voltage in the output range, and the value 4095 always corresponds to the
highest voltage minus 1 LSB. The theoretical top end of the range corresponds to an output code of 4096 which
is impossible to achieve.
Note:
In this manual, the terms analog output, D/A, and DAC are all used interchangeably to mean the
conversion of digital data originating from the Hercules III computer hardware to an analog signal terminating at
an external source.