7. Electronics design¶
This week I will:
- Use the test equipment in my lab to observe the operation of a microcontroller circuit board (group project)
- Redraw the echo hello-world board, add (at least) a button and LED (with current-limiting resistor), check the design rules, make it, test it (individual project)
- extra credit: Simulate its operation. Render it.
Research¶
Results¶
- Installed and tested USB Oscilloscope - Parallax Propscope 25MHz
- Installed Eagle PCB design software and designed echo hello-world
- Used pcb.py|frep.py 250 after completing Eagle design
Code Example¶
#
# define board. Used Neil's example as a guide, but stuffed every part and
# made the traces "by hand"
#
w = .015
width = 1.5
height = 1.2
mask = .004
x = 1
y = 1
z = -.005
d = .06
pcb = PCB(x,y,width,height,mask)
IC1 = ATtiny44_SOICN('IC1\nt44')
pcb = IC1.add(pcb,x+.87,y+.77,z)
J1 = header_ISP('J1\nISP')
pcb = J1.add(pcb,IC1.x+.05,IC1.pad[7].y-.22,z,angle=90)
pcb = wire(pcb,w,
IC1.pad[8],
point(J1.pad[1].x,IC1.pad[8].y,z),
J1.pad[1])
pcb = wire(pcb,w,
IC1.pad[9],
point(J1.pad[3].x,IC1.pad[9].y,z),
J1.pad[3])
pcb = wire(pcb,w,
IC1.pad[7],
point(IC1.pad[7].x,J1.y+.02,z),
point(IC1.pad[7].x+.04,J1.y-.02,z),
point(J1.pad[4].x,J1.y-.02,z),
J1.pad[4])
pcb = wire(pcb,w,
IC1.pad[4],
point(J1.pad[5].x,IC1.pad[4].y,z),
J1.pad[5])
pcb = wire(pcb,w,
IC1.pad[14],
point(J1.x-.01,IC1.pad[14].y,z),
point(J1.x-.05,IC1.pad[14].y-.04,z),
point(J1.x-.05,J1.y+.02,z),
point(J1.x+.05,J1.y+.02,z),
point(J1.x+.05,J1.pad[2].y-.08,z),
point(J1.pad[6].x,J1.pad[2].y-.08,z),
J1.pad[6])
J2 = header_FTDI('J2 FTDI')
pcb = J2.add(pcb,x+width-.22,IC1.y-.0,z,angle=0)
pcb = wire(pcb,w,
J1.pad[2],
point(J2.x,J1.pad[2].y,z),
point(J2.x+.08,J1.pad[2].y+.08,z),
point(J2.x+.08,J2.pad[3].y,z),
J2.pad[3])
pcb = wire(pcb,w,
IC1.pad[13],
point(IC1.pad[13].x+.105,IC1.pad[13].y,z),
point(IC1.pad[13].x+.105,J2.pad[4].y,z),
J2.pad[4])
pcb = wire(pcb,w,
IC1.pad[12],
point(IC1.pad[12].x+.07,IC1.pad[12].y,z),
point(IC1.pad[12].x+.07,J2.pad[5].y+.04,z),
point(IC1.pad[12].x+.11,J2.pad[5].y,z),
J2.pad[5])
XTAL1 = XTAL_EFOBM('XTAL1\n20 MHz')
pcb = XTAL1.add(pcb,IC1.pad[4].x-.3,IC1.pad[13].y+.003,z,angle=-90)
pcb = wire(pcb,w,
IC1.pad[2],
point(XTAL1.x+.12,IC1.pad[2].y,z),
point(XTAL1.x+.12,XTAL1.pad[1].y,z),
XTAL1.pad[1])
#pcb = wire(pcb,w,
# J1.pad[6],
# point(J1.pad[6].x,J1.pad[6].y-.08,z),
# point(XTAL1.x-.04,J1.pad[6].y-.08,z),
# point(XTAL1.x-.12,J1.pad[6].y,z),
# point(XTAL1.x-.12,XTAL1.pad[2].y,z),
# XTAL1.pad[2])
pcb = wire(pcb,w,
IC1.pad[3],
XTAL1.pad[3])
R1 = R_1206('R1\n10k');
pcb = R1.add(pcb,IC1.pad[1].x,IC1.pad[1].y+.1,z)
pcb = wire(pcb,w,
R1.pad[1],
IC1.pad[1])
pcb = wire(pcb,w,
J2.pad[3],
point(J2.pad[3].x+.08,J2.pad[3].y,z),
point(J2.pad[3].x+.08,R1.y+.06,z),
point(R1.pad[1].x,R1.y+.06,z),
R1.pad[1])
pcb = wire(pcb,w,
R1.pad[2],
point(J1.pad[5].x,R1.y,z),
J1.pad[5])
C1 = C_1206('C1\n1uF');
pcb = C1.add(pcb,IC1.pad[14].x,R1.y,z)
pcb = wire(pcb,w,
IC1.pad[14],
C1.pad[2])
pcb = wire(pcb,w,
C1.pad[1],
point(C1.pad[1].x,C1.y+.06,z))
pcb = wire(pcb,w,
J2.pad[1],
C1.pad[2])
S1 = button_6mm('S1\nButton');
pcb = S1.add(pcb,J1.pad[5].x-.4,IC1.pad[7].y-.245,z)
pcb = wire(pcb,w,
IC1.pad[5],
point(S1.x+.125,IC1.pad[5].y,z),
S1.pad[4])
pcb = wire(pcb,w,
S1.pad[3],
J1.pad[6])
R2 = R_1206('R2\n10k');
pcb = R2.add(pcb,S1.pad[2].x+.4,J1.pad[4].y,z,angle=-90)
pcb = wire(pcb,w,
R2.pad[1],
S1.pad[4])
pcb = wire(pcb,w,
R2.pad[2],
point(R2.pad[2].x,R2.pad[2].y-.07,z),
point(J1.pad[2].x,J1.pad[2].y-.13,z),
J1.pad[2])
#J2.pad[3],
# point(J2.pad[3].x+.08,J2.pad[3].y,z),
# point(J2.pad[3].x+.08,R1.y+.06,z),
# point(R1.pad[1].x,R1.y+.06,z),
# R1.pad[1])
LED1 = LED_1206('LED1\nLED')
pcb = LED1.add(pcb,S1.pad[1].x+.05,IC1.pad[7].y,z)
pcb = wire(pcb,w,
LED1.pad[1],
point(LED1.x-.055,XTAL1.pad[2].y,z),
XTAL1.pad[2])
pcb = wire(pcb,w,
S1.pad[3],
LED1.pad[1])
R3 = R_1206('R3\n499');
pcb = R3.add(pcb,S1.pad[3].x,IC1.pad[7].y,z)
pcb = wire(pcb,w,
R3.pad[2],
IC1.pad[6])
pcb = wire(pcb,w,
LED1.pad[2],
R3.pad[1])
- Used pcb.py and frep.py to “Design It” and generate these images to bring into mods
- “Make It”
- “Test It”
