Diamond Power Products MM-48-AT User Manual
Page 20
Diamond-MM-48-AT User Manual V1.01
Page 20
Base + 10
Write
FIFO Control Register
Bit
No.
7 6 5 4 3 2 1 0
Name
PAGE FIFOTH FIFOEN
SCANEN
PAGE
Page number for registers at Base + 12 through Base + 15
Page 0:
82C54 counter/timer access
Page 1:
Calibration registers
FIFOTH
FIFO threshold: 0 = 1024 samples (half full), 1 = 256 samples (1/8 full)
FIFOEN FIFO
enable:
1 Enable FIFO operation; if interrupts are enabled, interrupt requests will occur
when the FIFO reaches or exceeds the threshold selected with FIFOTH.
0 Disable FIFO operation; if interrupts are enabled, interrupts will occur after
each A/D conversion or scan is completed.
SCANEN Scan
enable:
1
A/D scan mode enabled; FIFO will fill up with data for a single scan, and
ADBUSY will stay high until an entire scan is complete. If interrupts are
enabled, interrupts will occur at the end of the scan. If FIFOEN = 1 and
SCANEN = 1, the interrupt will occur at the end of the scan that causes
the FIFO to reach or exceed its half-full point (256 samples).
0
Scan mode disabled; the ADBUSY bit will remain high for a single
conversion
Base + 10
Read
FIFO Status Register
Bit
No.
7 6 5 4 3 2 1 0
Name OVF HF
8F
EF PAGE
FIFOTH
FIFOEN
SCANEN
OVF
FIFO overflow flag: 0 = no overflow, 1 = overflow
Overflow is defined as the state when the FIFO is full and another A/D
conversion occurs before any data is read out of the FIFO. In an overflow
condition the FIFO contents are preserved, and no new data will be written to the
FIFO. To clear an overflow condition, the FIFO must be reset with the FIFORST
bit in register 8.
8F
FIFO 1/8 full flag:
0
FIFO is less than 1/8 full (256 samples)
1
FIFO is greater than or equal to 1/8 full
HF
FIFO half full flag
0
FIFO is less than half full (1024 or less samples)
1
FIFO is greater than half full (1025 or more samples)
EF
FIFO empty flag: 0 = FIFO is not empty, 1 = FIFO is empty
PAGE
Readback of PAGE bit described above
FIFOTH
Readback of FIFO threshold bit described above
FIFOEN
Readback of FIFOEN bit described above
SCANEN Readback of SCANEN bit described above