PMODJSTK datasheet(2/3 Pages) ETC1

2 / 3 page

Digilent, Inc.

PmodJSTK Reference Manual

www.digilentinc.com

page 2 of 3

The two least significant bits of the upper byte,

along with the entire lower byte, make up the

10-bit value that was calculated.

By referring to the Joystick Axis Map located

above, it is possible to know what X and Y

values to expect from the PmodJSTK, based

on the current position of the joystick.

The X and Y position data make up the first

four bytes of the five byte series. The last byte

contains the positions of the three buttons,

indicated by the three least significant bits in

the byte.

Communication

The serial peripheral interface (SPI) mode 0

method of communication is used to

communicate between the PmodJSTK and the

master board

To receive data from the PmodJSTK using

SPI, a byte must be shifted into the

PmodJSTK. As the byte is shifted into the

PmodJSTK, it shifts out a data byte to the

master. This communication is accomplished

via the master-in slave-out (MISO) and master-

out slave-in (MOSI) lines of the communication

bus. This communication must be

synchronously clocked using the serial clock

(SCK) line of the communication bus.

The PmodJSTK is enabled on the SPI bus by

lowering the slave select (SS) pin. The SS pin

is active low. The maximum recommended

SPI clock speed is 1 MHz. The minimum

recommended amount of time between the SS

pin going low and the start of data transmission

on the bus is 15µs. The minimum

recommended amount of time between the

end of one byte being shifted and the

beginning of the next is 10µs. The SS pin

should be returned high after communication

has been completed.

After lowering the SS pin, the master should

shift 5 bytes to the PmodJSTK in order to

receive data from the PmodJSTK. After each

of these bytes is shifted in, the master will have

received a byte of data from the PmodJSTK.

The two programmable LEDs located on the

PmodJSTK are turned on or off based on the

status of the first of the five bytes shifted into

the PmodJSTK. The two least significant bits

of the first byte determine the status of the

LEDs. For example, if the first byte shifted into

the PmodJSTK is 0b00 (0x00), then both LEDs

will be off. If the first byte is 0b01 (0x01), only

LED1 will be on and similarly if 0b10 (0x02) is

shifted in, then only LED2 will be on. Both will

be turned on if 0b11 (0x03) is shifted in as the

first byte. Write to the LEDs using the

following format:

Figure 3 LED Command

The remaining four bytes that are shifted in are

ignored by the PmodJSTK. After each byte

has been completely shifted in, the PmodJSTK

will have finished shifting out a byte of data to

the master.

The order of the bytes being transferred from

the PmodJSTK to the master is as follows:

X (low)

X(high)

Y (low)

Y(high)

Buttons

The buttons are reported in the last byte in the

following format:

Figure 4 Byte 5

A bit written to a ‘1’ indicates that the

corresponding button is being depressed, and

a ‘0’ indicates that it is not being depressed.

PMODJSTK Datasheet(PDF) 2 Page - List of Unclassifed Manufacturers

PMODJSTK Datasheet(HTML) 2 Page - List of Unclassifed Manufacturers

Html Pages

1 2 3

Datasheet Download

Link URL