Regarding LEDs of Bank 1 lighting up unexpectedly, I went back to the information you got about your board:

..."[color=rgb(0,0,0);font-family:arial, sans-serif;font-size:13px;]On the left-hand chip (Bank 0) A0 is pulled to ground through 10K?. On the right hand chip (Bank 1) A0 is pulled up to Vcc.[/color]

[color=rgb(0,0,0);font-family:arial, sans-serif;font-size:13px;]On both chips A1 and A2 are both pulled down to ground through 10K?, and the two solder jumpers BA0 and BA1 can be shorted to link A1 and A2 to Vcc respectively"....[/color]

As the board manufacturer describes it, this would result in the first chip (Bank 0) getting {A0,A1,A2} = {0,0,0} corresponding to hwAddr 0 (zero) which would be correct in reference to your code.

It shouldn't matter if I have got the bit order wrong in my code because we're dealing with all zeroes for Bank 0.

However, I think we should concentrate on getting rid of any exceptions first before investigating this any further.

...The GetHashCode method can be overridden by a derived type. If GetHashCode is not overridden, hash codes for reference types are computed by calling the Object.GetHashCode method of the base class, which computes a hash code based on an object's reference; for more information, see RuntimeHelpers.GetHashCode. In other words, two objects for which the ReferenceEquals method returns true have identical hash codes...

I'm sorry it's not working out as hoped. It's a bit strange since "port0000" would be the GPIO_NONE pin and that an attempt has been made to use it more than once. I'm thinking maybe the cast returns zero for some reason? This occurs while in the loop creating one of the output ports right? EDIT #1: Pin numbers can be given in any numeric format, the binary value will be the same either way.

EDIT #2: Made a few small updates to the code, probably nothing but you could try updating.

EDIT #3: What does your main chip and port creation code look like at this point?

Carrying the multi SPI conversation on here...
Do you think it is possible to incorporate Steffan's multi spi mgr in to your MCP23S17 driver?

Am I correct in saying the use of a bus is to allow for multiple port changes to be made in one write, thus increasing speed and efficiency?

If this is correct, then I also understand that I can't make a bus spanning multiple chips, however if for example I wanted to change the state of 10 pins 5 on each chip, then I could create a class that identifies which pins are on which bus and perform 2 writes one for each bus?

Outs[23].Value = true;

// create driver to use SPI bus #1 and Netduino pin 17 for chip selectvar chip = new MCP23S17(var io = new MCP23S17(SPI.SPI_module.SPI1, Pins.GPIO_PIN_17);// create a port for pin 1var outport = chip.CreateOutputPort(MCP23S17.Pins.GPIO_1);// drive pin 1 highoutport.Value = true;

Found an embarrassing bug in the multi SPI mgr - code is updated and hopefully problem is gone now...

Btw, your blinker loop looks suspicious - shouldn't you have a delay during the OFF period as well?

....Any ideas?...

for (int ic = 0; ic < icCnt; ic++){    chip[ic] = new MCP23S17(SPI_Devices.SPI1, Pins.GPIO_PIN_D10, Pins.GPIO_NONE, ic, 7000);    // Define all outputs    for (int pin = 0; pin < pinCnt; pin++)        Outs[16 * ic + pin] = chip[ic].CreateOutputPort((MCP23S17.Pins)(1 << pin), false);}

I guess I could add another constructor to better suit your needs, but it turns out its a little more complicated than that.

For now you can specify Cpu.Pin.GPIO_NONE for the IRQ pin like so for the first chip using hwAddr=0:

var chip0 = new MCP23S17(SPI.SPI_module.SPI1, Pins.GPIO_PIN_17, Cpu.Pin.GPIO_NONE, 0, 7000);

var chip1 = new MCP23S17(SPI.SPI_module.SPI1, Pins.GPIO_PIN_17, Cpu.Pin.GPIO_NONE, 1, 7000);

However, because I never got around to testing the driver in cascaded mode with multiple chips, it turns out it currently doesn't support running two instances simultaneously. This means that, until further, you'll have to settle for using one of your chips at a time.

I'm afraid you have to bare with me until I've had the time to add support for sharing the same SPI module between multiple instances.

Ok, I've fixed the hwAddr bug and updated the driver source code file of the first post in this thread.

About your board, I can't find any schematics and can't tell from just looking at the pictures how the A0,A1,A2 pins of the chips are connected but looking into their source code, it seems one chip has h/w address 0 (zero) and the other has h/w address 1 so you should just pass in those values and it should work.

This means you have to create one driver instance for each of the chips.

At a first glance, it seems they haven't broken out the IRQ pins of the chips which is too bad because then you cannot use the interrupt functionality of the driver.

The driver class has multiple constructors, normally you simply choose the one that fits your needs, e.g. the one without the IRQ pin parameter but when come to think of it, I'm uncertain as of there is a constructor that 1) has the hwAddr parameter and 2) does not have the IRQ pin parameter. I'll have to look into this and will get back to you.

Here's a series of example on how to use the driver.

using MCP23S17Lib;// print code versionDebug.Print(MCP23S17.Version);// create a new instance of the driver class using pin 17 for !CS and pin 18 for IRQvar io = new MCP23S17(SPI.SPI_module.SPI1, Pins.GPIO_PIN_17, Pins.GPIO_PIN_18);// create an input port for MCP23S17 pin 0var p0 = io.CreateInputPort(MCP23S17.Pins.GPIO_0);// create an input port for MCP23S17 pin 1var p1 = io.CreateInputPort(MCP23S17.Pins.GPIO_1);// create an output port for MCP23S17 pin 2var p2 = io.CreateOutputPort(MCP23S17.Pins.GPIO_2);// set p2 to the logical AND between p0 and p1p2.Value = p0.Value && p1.Value;// toggle p2 a few times (really quickly)p2.BurstWrite(new bool[]{true, false, true, false, true, false});// create an interrupt port for pin 12. Apply a weak pull up and have it fire interrupts on low edgesvar ip12 = io.CreateInterruptPort(MCP23S17.Pins.GPIO_12, MCP23S17.PullupMode.Pullup, MCP23S17.InterruptMode.EdgeLow);// attach an interrupt handler to pin 12ip12.OnInterrupt += (MCP23S17.Pins pin, bool value, DateTime time) =>    {        Debug.Print("Interrupt occurred on p12!");    };// quick and dirty single line interrupt handler on pin 14 with defaults (no pull up, both edges)io.CreateInterruptPort(MCP23S17.Pins.GPIO_14).OnInterrupt += (MCP23S17.Pins pin, bool value, DateTime time) =>    {        Debug.Print("Interrupt occurred on pin " + pin.ToString());    };// create a 4 pin output bus (MSB first)var bus = io.CreateBus (    io.CreateOutputPort(MCP23S17.Pins.GPIO_6),    io.CreateOutputPort(MCP23S17.Pins.GPIO_5),    io.CreateOutputPort(MCP23S17.Pins.GPIO_4),    io.CreateOutputPort(MCP23S17.Pins.GPIO_3));// set pins 6 and 4 to logic highbus.Value = 10;// create a 5 bit mixed bus of both inputs and outputs// which must be consecutive (e.g. not scarse)var mixbus = io.CreateBus(    io.CreateInputPort(MCP23S17.Pins.GPIO_11),    io.CreateOutputPort(MCP23S17.Pins.GPIO_10),    io.CreateInputPort(MCP23S17.Pins.GPIO_9),    io.CreateOutputPort(MCP23S17.Pins.GPIO_8),    io.CreateOutputPort(MCP23S17.Pins.GPIO_7));// this will only effect output pinsmixbus.Value = 0xffff;// this will read all five pins ushort mixbusvalue = mixbus.Value;// attach an interrupt handler to the mixed bus mixbus.OnInterrupt += (ushort interruptmask, ushort value, DateTime time) =>{    Debug.Print("Interrupt occurred!nBus value is " + value.ToString());

The above example uses SPI module #1 and pins 17 and 18 on a Netduino mini but you can easily change it to work on other pins and on any Netduino model, just change the first lines.

Yes it is because you are passing in the same SPI module to multiple driver instances.

As I said earlier, the driver does not yet support the same SPI module being shared among multiple driver instances.

I have to make a few adjustments for that first.

Also, I think your pin numbering might still be wrong - you must use values that are integer power of two, e.g. 1,2,4,8,16, etc. Have a look at the example I provided in post #15 above where I'm bit shifting like this "1 << Counter".

While waiting for me to update the code, you'd probably benefit more from verifying the driver works in getting a single single chip up and running.

Cool, so you "only" need to write your own LcdProvider class where you would then make internal use of the MCP23S17 driver in creating and using a bus from the pins you supply in the parameter list above - correct?

for (uint Counter = 0; Counter < pinCount; ++Counter)    Outs[Counter] = chip1.CreateOutputPort((MCP23S17.Pins)(1 << Counter), false);

ok.. another great work Andy. so... actually i dont need to drive LCD display using M74HC595. I think it should be easier to drive it using MCP2317.... thanks in advance for hanz and andy.