Root/TODO

Source at commit 57874cf5e2810158886e2f4e9d90e75d559dfa97 created 8 years 9 months ago.
By Werner Almesberger, Revert TVS size reduction. We're not ready for it yet.
1General
2=======
3
4Things not done yet
5-------------------
6
7- document directory hierarchy
8
9- make sure all files have a copyright header or are listed in AUTHORS
10
11- connect all the bits and pieces of the build system
12
13- combine io-parts.h generation
14
15- combine "standard" EP0 commands, such as *_ID and *_BUILD
16
17- implement return to DFU in application's EP0 protocol
18
19- consider removing *_ID and using bcdDevice instead
20
21
22Bugs to fix
23-----------
24
25- builds fail if .version isn't there yet
26
27
28
29atrf
30====
31
32AT86RF230-based IEEE 802.15.4 transceiver. Two variants: one to make a USB
33dongle for use with any Linux host, and one that connects with SPI directly
34inside a Ben.
35
36Update: following Rikard Lindstrom's revelation that we can use the uSD slot
37also just as general GPIOs, the variant that goes inside the Ben can wait a
38bit and the atusd board for insertion into the uSD slot is being worked on
39first. We can verify most of the design of a fully integrated board with the
40atusd board and the latter will be of greater immediate use.
41
42
43Things done
44-----------
45
46- verify that the Ben can output an a) 16 MHz clock, and b) with +/- 40 ppm
47
48  Done, see ecn/ecn0005.txt. Works fine.
49
50- replace discrete balun and filter with integrated solution, to reduce BOM
51  size, maybe cost, insertion loss, and PCB space (see ATRF/ECN0003)
52
53  Done for atusd. At a first glamce, does not seem to affect performance.
54
55- check if we really need three DC blocking caps in the RF path
56
57  Reduced to two in atusd without apparent ill effects.
58
59
60Things not done yet
61-------------------
62
63- examine spectrum around carrier frequency and first harmonic to look for
64  obvious distortions. Vary transmit power.
65
66- measure throughput as a function of placement/distance, carrier frequency,
67  and transmit power
68
69- atspi-txrx: suppport "extended mode" with IEEE 802.15.4 CSMA-CA for more
70  realistic throughput figures
71
72- measure full spectrum (ideally up to 25 GHz, but just 2nd and 3rd harmonic
73  will already tell most of the story) with calibrated antenna for FCC/ETSI
74  compliance assessment. Vary transmit power.
75
76- use IEEE 802.15.4 stack from linux-zigbee. The linux-zigbee kernel is
77  currently at 2.6.35. Once 2.6.36 is released, we should have Ben and
78  IEEE 802.15.4 support in the same kernel without further ado.
79
80- change layout of transceiver side of the board for placement inside Ben
81
82- define EMI filters for placement inside Ben
83
84- check USB standard for recommended USB dongle dimensions
85
86- change layout for straight USB dongle
87
88- generate proper BOM
89
90- implement sleep mode
91
92- (atusd) verify SPI signal timing, particularly the data clock
93
94
95Bugs to fix
96-----------
97
98- atrf vs. atspi naming is a bit confusing. Rename atrf hardware to atusb,
99  and maybe the tools from atspi to atrf ?
100
101
102ccrf
103====
104
105Board similar to the atrf, but with the TI/Chipcon CC2520.
106
107Cancelled. The CC2520 falls under US export restrictions, apparently because
108it contains an AES engine.
109
110
111cntr
112====
113
114Simple USB-based counter to measure a clock's long-time accuracy with
115arbitrarily high precision, by comparing it to an NTP time reference.
116
117
118Things not done yet
119-------------------
120
121- measure duty cycle
122
123- use the LED to display activity on clock input and duty cycle
124
125- consider using a comparator and a DAC to allow for programmable logic levels
126
127- evaluate termination resistance
128
129- document circuit design
130
131- record beats between 16 bit counter polls and use them for the estimate
132  of lost cycles (2*1 is way too optimistic)
133
134- include system clock resolution in accuracy calculation
135
136- consider running shorter sliding windows to estimate drift
137
138- consider detecting unusual half-periods
139
140- consider using a reversed USB connector, to avoid having to cross D+/D- and,
141  worse, VBUS and GND
142
143- test input performance by counting a source that emits a known number of
144  cycles
145
146- consider using historical margins to sanity-check the current margin (if any
147  old.max < curr.min or old.min > curr.max, we have a problem) and to further
148  narrow the effective margin, thus achieving faster convergence. We would have
149  to consider temperature drift of the frequency source in this case.
150
151- find out why frequency measurements always seem to start high and then slowly
152  drop
153

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