Epson S5U1C63007P Manual page 10

CHAPTER 3: PRECAUTIONS ON USING THE S5U1C63007P PERIPHERAL CIRCUIT BOARD
d) Voltage doubler ON/OFF circuit (DBON)
e) Voltage halver ON/OFF circuit (HLON)
f) Oscillation system voltage regulator power supply select circuit (VDSEL)
g) LCD system voltage regulator power supply select circuit (VCSEL)
h) SVD criteria voltage setting circuit (SVDS0–3)
i) SVD ON/OFF circuit (SVDON)
j) LCD power supply ON/OFF circuit (LPWR)
k) LCD constant-voltage switching circuit (VCCHG)
l) DTMF tone output circuit (TONE)
m) FSK ON/OFF circuit (FSKON)
- Those that require attention during system and software design
n) Currents consumed by internal pull-up resistors
o) Input ports in a floating state
(3) Functional difference
<LCD power supply circuit>
There is a delay between the time the LCD power supply circuit (LPWR) is turned on and the time the
LCD drive waveform is output. This delay on the S5U1C63007P board is set to 107 msec. The delay on
an actual IC is different, however. Consult the technical hardware manual.
<SVD circuit>
- This board also supports SVD circuit that detects the voltage supplied from outside the terminal. The
reference voltage is set to approximately 1.05 V. The SVD function for the internal voltage is evaluated
by artificially changing the power-supply voltage using the VSVD control on the S5U1C63007P board.
- There is a delay between the time the power to the SVD circuit is turned on and the time the SVD data
is detected. This delay on the S5U1C63007P board is set to between 61 and 92 µsec. For the delay on an
actual IC, consult the technical hardware manual to ensure that there is a sufficient delay before the
output voltage is detected.
<Oscillator circuit>
- There must be a waiting period between the time the OSC3 oscillation control circuit (OSCC) is turned
on and the moment at which oscillation stabilizes. The oscillator on the S5U1C63007P board can
operate when it is switched to OSC3 without the insertion of a waiting period. Therefore, consult the
technical hardware manual to set an appropriate waiting period on the actual IC.
- Separate instructions should be used to switch the clock from OSC3 to OSC1, and to stop the OSC3
circuit from oscillating. If these operations are performed simultaneously by one instruction, care
should be exercised. Although such operations are performed normally on the S5U1C63007P board,
an actual IC may not perform correctly.
- When using an external clock, make sure that it is adjusted for an amplitude of 5 V ± 5% and for a
duty cycle of within 50% ± 10%, and that it is input from the I/O connectors OSC1 and OSC3 with V
set for GND.
- The actual IC does not support CR oscillation for both OSC1 and OSC3.
- Since the logic level on the S5U1C63007P board is high, its oscillation starting and oscillation stopping
times are different from those of an actual IC.
- The S5U1C63007P board contains oscillators for the OSC1 and OSC3. If the OSC3 oscillator is not used
on an actual IC, care should be exercised because operations are performed on the emulation board by
using its OSC3 circuit.
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EPSON
S5U1C63007P MANUAL (PERIPHERAL CIRCUIT
BOARD FOR S1C63557/63558/63567)
SS