Hercules-EBX CPU User Manual V1.02
Page 86
AINTE FIFOEN
SCANEN
Operation
0 0 0
Single A/D conversions are triggered by write to Base+15, bit 0.
ADBUSY = ADSTS (from A/D)
No interrupt occurs.
The user program monitors ADBUSY and reads A/D data when it goes low.
0 0 1
A/D Scans are triggered by write to Base+15, bit 0. All channels between LOW
and HIGH will be sampled.
ADBUSY goes high at the first ADSTS high pulse and stays high until the last
ADSTS pulse goes low.
No interrupt occurs.
The user program monitors WAIT and then reads the A/D data when it goes low.
0
1
0
Same operation as case 000 above. The FIFO is not used in this case.
0
1
1
Same operation as case 001 above. The FIFO is not used in this case.
1 0 0
Single A/D conversions are triggered by the source selected with CLKSEL.
ADBUSY = ADSTS
INT goes high after each conversion is done (when ADBUSY goes low).
The interrupt routine reads one A/D sample each time it runs.
1 0 1
A/D Scans are triggered by the source selected with CLKSEL.
ADBUSY goes high at the first ADSTS high pulse and stays high until the last
ADSTS pulse goes low.
INT goes high after the last ADBUSY pulse goes low (i.e. when WAIT goes low).
The interrupt routine reads out one entire A/D scan each time it runs.
1 1 0
Single A/D conversions are triggered by the source selected with CLKSEL.
ADBUSY = ADSTS
A/D interrupt occurs when the FIFO reaches its programmed threshold.
The interrupt routine reads out a number of samples equal to the FIFO threshold
each time it runs.
1 1 1
A/D scans are triggered by the source selected with CLKSEL.
ADBUSY goes high at the first ADSTS high pulse and stays high until the last
ADSTS pulse goes low.
INT goes high after the last ADBUSY pulse goes low (i.e. when WAIT goes low)
AND an integral no. of scans has occurred and the FIFO threshold is reached.
The interrupt routine reads out a number of samples equal to the FIFO threshold
each time it runs.
Table 34: A/D Operating Modes
