SPI connector pinout

For the interconnect between the SPI masters and the SPI expansion boards BitWizard uses a 6-pin SPI cable.

The pinout is the same (or very similar) to the pinout of the 6-pin ICSP programming connector that lots of AVR boards have.

pin	function	remark
1	MISO	Master In Slave Out
2	VCC	power
3	SCK	Shift Clock
4	MOSI	Master Out Slave In.
5	SS	Slave Select
6	GND	Ground 0V

The connector is laid out as follows:

1	2
3	4
5	6

The board usually has pin 1 and six marked.

Connecting the BitWizard boards to an Arduino

pin	function	arduino pin
1	MISO	12
2	VCC	5V
3	SCK	13
4	MOSI	11
5	SS	10
6	GND	Gnd

You could use other pins, but then you have to make a software SPI implementation. This is not too difficult, but might be neccesary if something else is already on the SPI pins. On the other hand, you might be able to still use the hardware SPI module by just moving the "SS" pin somewhere else.

Arduino tells me that with differing chips being used as the "heart" of the module, the SPI pins are always available on the connector marked "ISP". The pin 5 or slave select is connected to the reset line, so it is not available to drive external slave select.

On BitWizard Raspduino and ftdiatmega boards you can chose if that connector becomes SPI out or ISP.

Connecting the BitWizard boards to a Raspberry pi

pin	function	Raspberry pi P1 pin
1	MISO	21 GPIO 9
2	VCC	2,4 5V
3	SCK	23 GPIO 11
4	MOSI	19 GPIO 10
5	SS	24 CE0 or 26 CE1
6	GND	6, 9, 14,20,25 Gnd

You could use other pins, but then you have to make a software SPI implementation. This is not too difficult, but might be neccesary if something else is already on the SPI pins.