ST7585
Pin Name
Type
Description
No. of Pins
Read/Write execution control pin. When parallel interface is selected:
MPU Type
ERD
Description
Read/Write control input pin.
R/W=”H“: When E is “H”, D[7:0] are in an
ERD
6800 series
E
output status.
I
R/W=”L“: Signals on D[7:0] are latched at
1
the falling edge of E signal.
8080 series
Read enable input pin.
/RD
When /RD is “L”, D[7:0] are in output status.
ERD is not used in serial interfaces and should fix to “H” by VDD1.
When using 8-bit parallel interface: 6800 or 8080 mode
I/O 8-bit bi-directional data bus. Connect to the data bus of 8-bit microprocessor.
When CSB is non-active (CSB=“H”), D[7:0] pins are high impedance.
When using serial interface: 4-LINE or 3-LINE
D7=SCLK : Serial clock input.
D6=SDA : Serial data input.
I
D5=A0 : Command / Data selection (unused in 3-Line SPI; fix to H by VDD1).
D4=CSB : Chip select pin.
D[7:0]
D[3:0] : Not used and should fix to “H” by VDD1.
8
When using I2C interface
D7=SCLK : Serial clock input.
D6=SDA_IN *1 : Serial data input.
D[5:3] : SDA_OUT *1 : Outputs for acknowledge-bit of the I2C protocol.
I, O D[2]= Not used and should fix to “H” by VDD1.
D[1:0]=SA[1:0] : Slave address bits. Must set to “H” by VDD1 or “L” by VSS1.
D[6:3] must connect together (SDA). *1
CSB is not used in I2C interface and should fix to “H” by VDD1.
Note:
1. By connecting SDA_IN and SDA_OUT externally, the SDA line becomes fully I2C interface compatible. Separating
acknowledge-output from serial data input is advantageous for chip-on-glass (COG) applications. In COG applications,
the ITO resistance and the pull-up resistor will form a voltage divider which affects acknowledge-signal level. Larger
ITO resistance will raise the acknowledge-signal level and system cannot recognize this level as a valid logic “0” level.
By separating SDA_IN from SDA_OUT, the IC can be used in a mode which ignores the acknowledge-bit. For
applications which check acknowledge-bit, it is necessary to minimize the ITO resistance of the SDA_OUT trace to
guarantee a valid low level.
2. After VDD1 is turned ON, any MPU interface pins cannot be left floating.
Ver 1.0c
9/51
2009/04/14