HD66503 Datasheet, PDF (9/27 Pages) Hitachi Semiconductor – (240-Channel Common Driver with Internal LCD Timing Circuit)

HD66503
1. CR Oscillator: The CR oscillator generates the HD66503 operation clock. During master mode, since
the operation clock is needed, connect oscillation resistor R_f with oscillation capacitor C_f as follows.
When the external clock is used, input external clock to pin CR and open pins C and R (Figure 4).
When using the HD66503 during slave mode, the operation clock will not be needed; therefore,
connect pin CR to V_CC and open pins C and R (Figure 5).
2. Liquid Crystal Timing Generator: The liquid crystal timing generator creates various signals for the
LCD. During master mode (M/6 = V_CC), the generator operates the HD66503’s internal circuitry as a
common internal driver using the generated LCD signals. In addition, signals CL1, M, and '2&
created by this generator can synchronously display data on a liquid crystal display by inputting them
into the RAM-provided segment driver HD66520 used together with HD66503. During slave mode
(M/6 = GND), this generator stops; the slave HD66503 operates based on signals CL1, M, '2&, and
FLM generated by the master HD66503.
3. M/$ Switcher: Controls the input and output of LCD signals CL1, FLM, M, and '2&.
This circuit outputs data when M/6 = V_CC (master mode) and inputs data when M/6 = GND (slave
mode).
4. Alternating Signal Generator: Generates the alternating signal for the liquid crystal display. Since
the alternating signal decreases cross talk, it can alternate among 2 to 63 lines. The number of lines
are specified with pins MWS0 to MWS5 is set to either V_CC or GND.
Moreover, the alternating signal can be externally input by grounding pins MWS0 to MWS5. In this
case, the alternating signal is input from pin M.
C
R
CR
OPEN OPEN
External clock
C
R CR
R_f
C_f
Figure 4 Oscillator Connection in Master Mode
C
R
CR
OPEN OPEN V_CC
Figure 5 Oscillator Connection in Slave Mode
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