PCF8531 datasheet(29/44 Pages) NXP

29 / 44 page

PCF8531_4

Product data sheet

Rev. 04 — 13 June 2008

29 of 44

NXP Semiconductors

PCF8531

34 x 128 pixel matrix driver

11.3 Command decoder

The command decoder identiﬁes command words that arrive on the I2C-bus. The most

signiﬁcant bit of a control byte is the continuation bit Co. If this bit is logic 1, it indicates

that only one data byte (either command or RAM data) will follow. If this bit is logic 0, it

indicates that a series of data bytes (either command or RAM data) may follow. The DB6

bit of a control byte is the RAM data/command bit RS. When this bit is at logic 1, it

indicates that another RAM data byte will be transferred next. If the bit is at logic 0, it

indicates that another command byte will be transferred next.

• Pairs of bytes; information in the second byte, the ﬁrst byte determines whether

information is display or instruction data

• Stream of information bytes after Co = 0; display or instruction data, depending on

last RS (Register Selection).

PCF8531 Datasheet(PDF) 29 Page - NXP Semiconductors