Two ports, one 6 bit control port and one 8 bit io port. The power up reading of the control port (with weak pull up's) tells the UNIO what mode to operate in. Modes that do not use all 6 control port lines are identified because they have the left over lines pulled (or jumpered) low on the circuit board.
|111111||En, Addr, Data||4 bit by two addressable latch|
|011111||-, Addr, Data||4 bit by two addressable latch||Lack of clock is compinsated for by watching all lines for 0.5 clock cycles after any change is detected and updateing output pins only after this "settleing time"|
|1110 11||En, Data, -, Addr||2 bit by four addressable latch|
|0110 11||-, Data, Addr||2 bit by four addressable latch|
|101 111||En, -, Data, Addr[0..3]||1 bit by eight addressable latch|
|010 111||-, Data, -, Addr[0..3]||1 bit by eight addressable latch|
|1111 10||SCK, SI, SO, *CE, 1, 0||SPI|
|1011 10||SCK, -, SI+SO, CE, 1, 0||SPI (3 pin)||SO connected to SI thru resistor|
|1111 00||SCK, SI, SO, CE, 0, 0||SPI <-> Serial||RX, TX, *CE, are the first three pins of the 8 bit IO port|
|1111 01||SCK, SI, SO, CE, 0, 1||SPI <-> I2C||SCL, SDA, -, *CE are the first four pins of the 8 bit IO port.|
|1100 01||SCL, SDA, -, -, 0, 1||I2C||Basically a shift register|
|1101 01||SCL, SDA, -, *CE, 0, 1||I2C with *CE||Several shift registers connect to the same data and clock lines with seperate chip selects|
|1111 01||SCL, SDA, CLR, *CE, 0, 1||I2C with *CE and CLR||Shift register with enable and clear.|
|1101 00||SCL, SDA, -,*CE, 0 , 0||I2C <-> Serial||Allows us to debug I2C interfaces.
|0100 00||-, TX, -, -, 0, 0||Serial Out|
|1000 00||RX, -, -, -, 0, 0||Serial In|
|0110 00||-, TX,*CE, -, 0, 0||Serial Out with *CE|
|1010 00||RX, -, *CE, -, 0, 0||Serial In with *CE|
|1100 00||RX, TX, -, -, 0, 0||Serial IO|
|1110 00||RX, TX, *CE, -, 0, 0||Serial IO with *CE|
Notice that the first line of the 6 bit control port is the IRQ line.
|file: /Techref/idea/unio.htm, 4KB, , updated: 2002/5/6 16:26, local time: 2018/9/24 23:54,
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<A HREF="http://www.sxlist.com/techref/idea/unio.htm"> Universal IO expander, UNIO</A>
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