ST7522 Sitronix, ST7522 Datasheet - Page 9

• Manufacturer Part Number: ST7522
• Description: 17 x 96 Dot Matrix LCD Controller
• Manufacturer: Sitronix

ST7522
The Serial Interface
When the serial interface has been selected (P/S = “L”) then
when the chip is in active state (CS1
serial data input (SI) and the serial clock input (SCL) can be
received. The serial data is read from the serial data input pin
in the rising edge of the serial clocks D7, D6 through D0, in
this order. This data is converted to 8 bits parallel data in the
rising edge of the eighth serial clock for the processing. The
* When the chip is not active, the shift registers and the counter are reset to their initial states.
* Reading is not possible while in serial interface mode.
* Caution is required on the SCL signal when it comes to line-end reflections and external noise. We recommend that operation
The Chip Select
The ST7522 Series chips have two chip select terminals:
CS1
enabled only when CS1
Ver 1.0c
―
be rechecked on the actual equipment.
CS2
SCL
CS1
A0
and CS2. The MPU interface or the serial interface is
SI
―
= “L” and CS2 = “H”.
―
= “L” and CS2 = “H”) the
D7
D6
D5
D4
Figure 1
D3
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A0 input is used to determine whether or the serial data input
is display data or command data; when A0 = “H”, the data is
display data, and when A0 = “L” then the data is command
data. The A0 input is read and used for detection every 8th
rising edge of the serial clock after the chip becomes active.
Figure 1 is a serial interface signal chart.
When the chip select is inactive, D0 to D7 enter a high
impedance state, and the A0, RD
inactive. When the serial interface is selected, the shift
register and the counter are reset.
D2
D1
D0
D7
D6
D5
―
, and WR
D4
―
D3
inputs are
2002/07/10
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