libngspice does not get built by default on macports

If you want to use PySpice, you first must have the library bindings installed. The Macports Portfile for ngspice does not build the libraries by default. Here's the symptom:

OSError: cannot load library 'libngspice.dylib': dlopen(libngspice.dylib, 2) : image not found. Additionally, ctypes.util.find_library() did not manage to locate a library called 'libngspice.dylib'

Basically, this means that there's just not a library. I couldn't find it anywhere, and then I realized that macports did not build the library by default.
Find where the portfile is:

sudo port file ngspice

Next, you have to edit it to add --with-ngshared:

    configure.args      --enable-cider \
                        --enable-xspice \
                        --enable-pss \
                        --with-editline \
                        --with-x \
                        --enable-debug=no \
                        --with-ngshared

Finally, you can build the port. If you have already installed it, you need to upgrade it:

sudo port -sn upgrade --force ngspice

I wish that there was some way to append a configuration argument via the command line, but I just cannot seem to make it work, even though there's a facility for it.

freehdl doesn't work as-is on macports

I had to add the following to the portfile:

configure.cxx_stdlib	libstdc++

PIC32MZ TFBGA pins are incorrect in the document

The PIC32MZ2048EFH144 is a fine MCU. I have code for both the LQFP-144 and the TFBGA-144, and there's not an obvious way to easily map between code version and the hardware pinouts. For this reason, I made a spreadsheet, and there were errors on the TFBGA-144 pinout. Please note the images below from version DS60001320G of the datasheet:

You will notice M11, M11 and Z13. Firstly, the issue is that there should never have duplicates, and then there's not a "Z" row on the BGA. The correct pins follow:

M11	RH15
K10	VSS
A13	RE3

The A13 was easy to guess, and I confirmed it by toggling the pin. The M11 I had tied to GND, and I confirmed this pin by watching the current fluxuate when I single stepped it while measuring current. The complete and correct pin list follows:

PIC32MZ144 QFP pin number	PIC32MZ144 TFBGA pin number	pin ID	voltage tolerance	name	function
1	A12	RG15
2	B12	RA5
3	A11	RE5
4	B11	RE6
5	B10	RE7
6	A10	RC1
7	C9	RJ8
8	B9	RJ9
9	A9	RJ12	5V
10	A8	RJ10	5V
11	B8	RC2
12	C8	RC3
13	D8	RC4
14	B7	RG6
15	C7	RG7
16	D7	RG8
17	D6	VSS
18	A7	VDD
19	C6	RK0	5V
20	B6	MCLR	5V
21	A6	RG9
22	D5	RA0
23	A5	RE8
24	B5	RE9
25	C5	RB5
26	A4	RB4
27	B4	RJ11
28	C4	RJ13	5V
29	C3	RJ14	5V
30	B3	RJ15	5V
31	C2	RB3
32	D4	VSS
33	A3	VDD
34	B2	RB2
35	A2	RB1
36	A1	RB0
37	B1	RB6
38	C1	RB7
39	D2	RA9
40	D3	RA10
41	D1	AVDD
42	E4	AVSS
43	E1	RH0
44	E2	RH1
45	E3	RH2	5V
46	F4	RH3	5V
47	F3	RB8
48	F2	RB9
49	F1	RB10
50	G1	RB11
51	G2	RK1	5V
52	G3	RK2	5V
53	G4	RK3	5V
54	H4	VSS
55	H1	VDD
56	H2	RA1
57	H3	RF13
58	J4	RF12
59	J3	RB12
60	J2	RB13
61	J1	RB14
62	K2	RB15
63	K4	VSS
64	K1	VDD
65	K3	RH4
66	M3	RH5
67	L3	RH6
68	L2	RH7	5V
69	M2	RD14
70	L1	RD15
71	M1	RC12
72	N1	RC15
73	N2	VBUS	5V
74	N3	VBUS3V3
75	L4	VSS
76	N4	D-
77	N5	D+
78	M4	RF3	5V
79	M5	RF2	5V
80	L5	RF8	5V
81	K5	RH8	5V
82	K6	RH9	5V
83	L6	RH10	5V
84	M6	RH11	5V
85	N6	RA2	5V
86	M7	RA3	5V
87	L7	RA4	5V
88	N7	VDD
89	K7	VSS
90	K8	RF4	5V
91	L8	RF5	5V
92	M8	RK4	5V
93	N8	RK5	5V
94	K9	RK6	5V
95	L9	RA14	5V
96	M9	RA15	5V
97	N9	RD9	5V
98	N10	RD10	5V
99	M10	RD11	5V
100	L10	RH12	5V
101	K11	RH13	5V
102	L11	RH14	5V
103	M11	RH15	5V
104	N11	RD0	5V
105	N12	RC13
106	M12	RC14
107	N13	VDD
108	K10	VSS
109	M13	RD1	5V
110	L12	RD2	5V
111	L13	RD3	5V
112	K13	RD12	5V
113	K12	RD13	5V
114	J11	RJ0	5V
115	J12	RJ1	5V
116	J13	RJ2	5V
117	H13	RJ3	5V
118	H12	RD4	5V
119	H11	RD5	5V
120	J10	RD6	5V
121	H10	RD7	5V
122	G13	VDD
123	G10	VSS
124	G12	RF0	5V
125	G11	RF1	5V
126	F10	RK7	5V
127	F11	RG1	5V
128	F12	RG0	5V
129	F13	RA6	5V
130	E13	RA7	5V
131	E12	RJ4	5V
132	E11	RJ5	5V
133	E10	RJ6	5V
134	D11	RJ7	5V
135	D10	RE0	5V
136	D9	VSS
137	D13	VDD
138	C10	RE1	5V
139	D12	RG14	5V
140	C11	RG12	5V
141	C12	RG13	5V
142	C13	RE2	5V
143	B13	RE3	5V
144	A13	RE4	5V

Renaming a KiCad project

I keep my projects in svn, and kicad made it more challenging than I expected to rename a project. The orignal project was igbt-tx, and my new project is tx-3x1. First, you rename the top level project:

for f in igbt-tx*; do svn mv "$f" "$(echo $f | sed 's/^igbt-tx/tx-3x1/g')"; done

You then need update the libraries:

find ./ -type f -exec sed -i 's/igbt-tx/tx-3x1/g' {} \;

If you want to do this without svn, you need to just remove the "svn".

kicad eeschema parts off grid

One of the challenges of collaboration is configuration. I found today that if you "right-click", you can change the schematic grid. I was having trouble with my grid being 1.5 times of the collaborator. 

 

converting between decimal and hex on the command line

I've never been on a *unix system without bc installed. (I was surprised recently as well that some Linux distributions do not include vi) Recently, I have had the need to convert decimal to hexadecimal and hexadecimal to decimal enough to warrant scripts.

#!/bin/sh
#dec2hex.sh
COMMAND=bc
if ! command -v $COMMAND &> /dev/null
then
    echo "$COMMAND could not be found"
    exit
fi 
echo "obase=16; $@" | $COMMAND

#!/bin/sh
#hex2dec.sh
COMMAND=bc
if ! command -v $COMMAND &> /dev/null
then
    echo "$COMMAND could not be found"
    exit
fi
echo "ibase=16; $@"|$COMMAND

FreeCAD via Macports under MacOS 10.13.6

There were all sorts of errors getting FreeCAD to install, but I found a ticket:
https://trac.macports.org/ticket/60039
Sadly, it still took me a bit to sort it out. You need python2.7 and boost.

sudo port select python27

If you do not have python27, install it. (however, it'll probably come with boost)

sudo port install boost @no_single+no_static+python27

At this point, you should be able to build FreeCad

sudo port install freecad