Data Sheet S10299EJ4V0DS00

11

If the C, /D input indicates command specifications, the data input from the CPU to the serial/parallel interface is

sent from the serial/parallel register to the command decoder for decoding.

In the write mode, if the C, /D input indicates data specifications, the data loaded to the serial/parallel register is

directly transferred to the data memory.

In the AND or OR mode, the data loaded into the serial/parallel register is ANDed or ORed with the data memory

contents, and the result is transferred to the data memory. In the character mode, the data loaded into the

serial/parallel register is regarded as ASCII or JIS code and is sent to the character generator. It is decoded to 5

×

7-bit character display pattern, and is stored into 5 successive data memory addresses.

Only when set to the read mode, can the serial/parallel interface output data to the CPU. When set to the read

mode, the serial/parallel interface always reads 8-bit data from the data memory and sets it in the serial/parallel register

for the next read operation.

In the serial interface mode, the data in the serial/parallel register is output from the SO pin with the MSB first at

each /SCK falling edge.

In the parallel interface mode, the upper 4 bits of the data in the serial/parallel register are output from the D3 to

D0 pins at the first falling edge of the /STB, and the lower 4 bits of the data in the serial/parallel register are output from

those pins at the second falling edge of the /STB.

In either the serial/parallel interface mode, each time 8 bits of data are output, the next 8 bits of data are

automatically read out from the data memory and set in the serial/parallel register.

2.2 Command Decoder

If the 8-bit data, input through the serial/parallel interface, is specified as a command (C, /D = 1), the data is

clocked in as a command, and is decoded to generate an internal control signal.

2.3 Character Generator

The character generator becomes effective, when a character mode setting command (SCML, SCMR) is

executed. In this case, 8-bit data written through the serial/parallel interface is interpreted as a character code, and the

5

× 7-dot matrix pattern, corresponding to the code, will be generated. It is transferred to the 5 successive addresses in

the data memory (7 bits

× 5 times).

The character generator contains the following 160 different pattern data :

ASCII

JIS

Upper-case alphabets 26

KATAKANA 55

Lower-case alphabets 26

Symbols

9

Numerical characters

10

Symbols

34

Figure 2–2 shows correspondence of character codes (ASCII/JIS) and 5 dots

× 7 dots display patterns. 96 codes

of 20H to 7FH correspond to ASCII characters, and A0H to DFH correspond to JIS characters.