54
EPSON
S1C60N02 TECHNICAL MANUAL
CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (A/D Converter)
Up/down counter (0E4H–0E7H)
Writing and reading is possible on a 4-bit basis by the up/
down counter that is used to adjust the CR oscillation time
between the reference resistance and the variable resistance
elements.
The up/down counter counts up during oscillation of the
reference resistance and counts down from the value it
reached when counting up to "0000H" during oscillation of
the sensor.
"0000H" needs to be entered in the counter prior to A/D
conversion in order to adjust the counting time of both
counts.
After an initial reset, data in this counter become indefinite.
Up-counter (0F5H–0F8H)
This counter counts up according to the CR oscillation
clock. It permits writing and reading on a 4-bit basis.
The complement of the number of clocks to be counted by
the oscillation of the reference resistance, must be entered
in this counter prior to A/D conversion.
If A/D conversion is initiated, the counter counts up from
the set initial value, first according to the oscillation clock of
the reference resistance. When the counter reaches "0000H"
due to overflow, the oscillation of the reference resistance
stops, and the sensor starts oscillating. The counter contin-
ues counting according to the sensor oscillation clock.
Counting time during the oscillation of the reference resist-
ance is calculated by the up/down counter TC0–TC15. Up-
counter C0–C15 stops counting when the same period of
time elapses. Difference from the reference resistance can be
evaluated from the value indicated by the counter when it
stops. Calculate the target value by processing the above
difference according to the program.
Measurable range and the overflow of the up/down counter
TC0–TC15 must be taken into account when setting an
initial value to be entered prior to A/D conversion.
After an initial reset, data in this counter become indefinite.
TC0–TC15
C0–C15