Data Sheet

4D SYSTEMS 4DPi-32-II Primary Display – Raspberry Pi Compatible
© 2018 4D SYSTEMS Page 15 of 18 www.4dsystems.com.au
4DPi
-32
-II Primary Display
– Raspberry
Pi
Example for communicating to Push Buttons, for Python:
#!/usr/bin/python
import array, fcntl
from time import sleep
# test program to read state of buttons on 4D Systems 4DPi displays
#LCD4DPI_GET_KEYS = -2147202303
_IOC_NRBITS = 8
_IOC_TYPEBITS = 8
_IOC_SIZEBITS = 14
_IOC_DIRBITS = 2
_IOC_DIRMASK = (1 << _IOC_DIRBITS) - 1
_IOC_NRMASK = (1 << _IOC_NRBITS) - 1
_IOC_TYPEMASK = (1 << _IOC_TYPEBITS ) - 1
_IOC_NRSHIFT = 0
_IOC_TYPESHIFT = _IOC_NRSHIFT+_IOC_NRBITS
_IOC_SIZESHIFT = _IOC_TYPESHIFT+_IOC_TYPEBITS
_IOC_DIRSHIFT = _IOC_SIZESHIFT+_IOC_SIZEBITS
_IOC_NONE = 0
_IOC_WRITE = 1
_IOC_READ = 2
def _IOC(dir, type, nr, size):
# print 'dirshift {}, typeshift {}, nrshift {}, sizeshift
{}'.format(_IOC_DIRSHIFT, _IOC_TYPESHIFT, _IOC_NRSHIFT, _IOC_SIZESHIFT)
ioc = (dir << _IOC_DIRSHIFT ) | (type << _IOC_TYPESHIFT ) | (nr << _IOC_NRSHIFT
) | (size << _IOC_SIZESHIFT)
if ioc > 2147483647: ioc -= 4294967296
return ioc
#def _IO(type, nr):
# return _IOC(_IOC_NONE, type, nr, 0)
def _IOR(type,nr,size):
return _IOC(_IOC_READ, type, nr, size)
#def _IOW(type,nr,size):
# return _IOC(_IOC_WRITE, type, nr, sizeof(size))
LCD4DPI_GET_KEYS = _IOR(ord('K'), 1, 4)
buf = array.array('h',[0])
print 'Press Top & Bottom buttons simultaneously to exit'
with open('/dev/fb1', 'rw') as fd:
while True:
fcntl.ioctl(fd, LCD4DPI_GET_KEYS, buf, 1) # execute ioctl call to read the
keys
keys = buf[0]
if not keys & 0b00001:
print "KEY1" ,
if not keys & 0b00010:
print "KEY2" ,
if not keys & 0b00100:
print "KEY3" ,
if not keys & 0b01000:
print "KEY4" ,
if not keys & 0b10000:
print "KEY5" ,
if keys != 0b11111:
print
if keys == 0b01110: # exit if top and bottom pressed
break
sleep(0.1)