ks0078 Samsung Semiconductor, Inc., ks0078 Datasheet - Page 46

• Manufacturer Part Number: ks0078
• Description: 34com/120seg Driver & Controller For Dot Matrix Lcd
• Manufacturer: Samsung Semiconductor, Inc.

KS0078
34COM/120SEG DRIVER & CONTROLLER FOR DOT MATRIX LCD
Interface with MPU in Serial Mode
When IM port input is "Low", serial interface mode is started. At this time, all three ports, SCLK (synchronizing transfer clock),
SID (serial input data), and SOD (serial output data), are used. If KS0078 is to be used with other chips, chip select port
(CS) can be used.
By setting CS to "Low", KS0078 can receive SCLK input. If CS is set to "High", KS0078 reset the internal transfer counter.
Before transfer real data, start byte has to be transferred. It is composed of succeeding 5 "High" bits, read write control bit
(R/W), register selection bit (RS), and end bit that indicates the end of start byte. Whenever succeeding 5 "High" bits are
detected by KS0078, it makes serial transfer counter reset and ready to receive next information.
The next input data are register selection bit that determine which register will be used, and read write control bit that
determine the direction of data. Then end bit is transferred, which must have "Low" value to show the end of start byte.
(Refer to Fig 13. Fig 14)
(1) Write Operation (R/W = 0)
After start byte is transferred from MPU to KS0078, 8-bit data is transferred which is divided into 2 bytes, each byte has 4 bit's
real data and 4 bit's partition token data. For example, if real data is "10110001" (D0 - D7), then serially transferred data
becomes "1011 0000 0001 0000" where 2nd and 4th 4 bits must be "0000" for safe transfer.
To transfer several bytes continuously without changing RS bit and R/W bit, start byte transfer is needed only at first starting
time. i.e., after first start byte is transferred, real data succeeding can be transferred.
(2) Read Operation (R/W = 1)
After start byte is transferred to KS0078, MPU can receive 8-bit data through the SOD port at a time from the LSB. Wait time
is needed to insert between start byte and data reading, as internal reading from RAM requires some delay.
Continuous data reading is possible such as serial write operation. It also needs only one start bytes, only if you insert some
delay between reading operations of each byte. During the reading operation, KS0078 observes succeeding 5 "High" from
MPU. If it is detected, KS0078 restarts serial operation at once and ready to receive RS bit. So in continuous reading
operation, SID port must be "Low".