Root/TODO

Source at commit b3b037e18d4ac2018cbef505b6ee3e01bfd24896 created 8 years 3 months ago.
By Werner Almesberger, TODO: update for switch to spi_atben
1Current stuff
2-------------
3
4- add spi_atben driver, for improved performance and to serve as an
5  example for spi_atusb
6
7  Resolution: done. Average frame buffer transfer speed increased from
8  about 0.82 Mbps to 4.2 Mbps. Things still pending:
9
10  - restore GPIOs in spi_atben
11  - update unbinding procedure
12
13- need to document fab workflow in makefiles/Makefile.kicad
14
15  Deadline: before FISL 12 :-)
16
17- boot.hex is now bigger than 4 kB. Need to split USB stack build into
18  "lean" and "fat" version.
19
20  Work-around: those wishing to build their boot loader should use
21  commit ce16a16.
22
23  Resolution: should work now (after the stack split). Still needs
24  testing.
25
26- atusb/fw/ design flaw: we can send an interrupt queued in EP1 after
27  a control transfer has happened that turns off the interrupt source
28
29  Work-around: seems that waiting for 10 ms gets it most of the time
30
31- atusb/fw/ should combine interrupts so that we don't have to read
32  IRQ_STATUS (this goal may conflict with the synchronization
33  requirement above, though)
34
35  Resolution: do less instead of more - we now don't even touch
36  IRQ_STATUS in the atusb firmware and just send a zero byte as an
37  indication that something has happened.
38
39- show WLAN channels in atrf-rssi -g
40
41  Resolution: done
42
43- atusb/fw/: think of a better way to re-enable INT0 after ATUSB_GPIO
44
45- atusb/fw/: remove obsolete atusb requests
46
47
48*** EVERYTHING BELOW NEEDS UPDATING ***
49
50General
51=======
52
53Things not done yet
54-------------------
55
56- document directory hierarchy
57
58- make sure all files have a copyright header or are listed in AUTHORS
59
60- connect all the bits and pieces of the build system
61
62- combine io-parts.h generation
63
64- combine "standard" EP0 commands, such as *_ID and *_BUILD
65
66- implement return to DFU in application's EP0 protocol
67
68- consider removing *_ID and using bcdDevice instead
69
70
71Bugs to fix
72-----------
73
74- builds fail if .version isn't there yet
75
76
77
78atrf
79====
80
81AT86RF230-based IEEE 802.15.4 transceiver. Two variants: one to make a USB
82dongle for use with any Linux host, and one that connects with SPI directly
83inside a Ben.
84
85Update: following Rikard Lindstrom's revelation that we can use the uSD slot
86also just as general GPIOs, the variant that goes inside the Ben can wait a
87bit and the atben board for insertion into the uSD slot is being worked on
88first. We can verify most of the design of a fully integrated board with the
89atben board and the latter will be of greater immediate use.
90
91
92Things done
93-----------
94
95- verify that the Ben can output an a) 16 MHz clock, and b) with +/- 40 ppm
96
97  Done, see ecn/ecn0005.txt. Works fine.
98
99- replace discrete balun and filter with integrated solution, to reduce BOM
100  size, maybe cost, insertion loss, and PCB space (see ATRF/ECN0003)
101
102  Done for atben. At a first glamce, does not seem to affect performance.
103
104- check if we really need three DC blocking caps in the RF path
105
106  Reduced to two in atben without apparent ill effects.
107
108
109Things not done yet
110-------------------
111
112- examine spectrum around carrier frequency and first harmonic to look for
113  obvious distortions. Vary transmit power.
114
115- measure throughput as a function of placement/distance, carrier frequency,
116  and transmit power
117
118- atrf-txrx: suppport "extended mode" with IEEE 802.15.4 CSMA-CA for more
119  realistic throughput figures
120
121- measure full spectrum (ideally up to 25 GHz, but just 2nd and 3rd harmonic
122  will already tell most of the story) with calibrated antenna for FCC/ETSI
123  compliance assessment. Vary transmit power.
124
125- use IEEE 802.15.4 stack from linux-zigbee. The linux-zigbee kernel is
126  currently at 2.6.35. Once 2.6.36 is released, we should have Ben and
127  IEEE 802.15.4 support in the same kernel without further ado.
128
129- change layout of transceiver side of the board for placement inside Ben
130
131- define EMI filters for placement inside Ben
132
133- check USB standard for recommended USB dongle dimensions
134
135- change layout for straight USB dongle
136
137- generate proper BOM
138
139- implement sleep mode
140
141- (atben) verify SPI signal timing, particularly the data clock
142
143
144ccrf
145====
146
147Board similar to the atrf, but with the TI/Chipcon CC2520.
148
149Cancelled. The CC2520 falls under US export restrictions, apparently because
150it contains an AES engine.
151
152
153cntr
154====
155
156Simple USB-based counter to measure a clock's long-time accuracy with
157arbitrarily high precision, by comparing it to an NTP time reference.
158
159
160Things not done yet
161-------------------
162
163- measure duty cycle
164
165- use the LED to display activity on clock input and duty cycle
166
167- consider using a comparator and a DAC to allow for programmable logic levels
168
169- evaluate termination resistance
170
171- document circuit design
172
173- record beats between 16 bit counter polls and use them for the estimate
174  of lost cycles (2*1 is way too optimistic)
175
176- include system clock resolution in accuracy calculation
177
178- consider running shorter sliding windows to estimate drift
179
180- consider detecting unusual half-periods
181
182- consider using a reversed USB connector, to avoid having to cross D+/D- and,
183  worse, VBUS and GND
184
185- test input performance by counting a source that emits a known number of
186  cycles
187
188- consider using historical margins to sanity-check the current margin (if any
189  old.max < curr.min or old.min > curr.max, we have a problem) and to further
190  narrow the effective margin, thus achieving faster convergence. We would have
191  to consider temperature drift of the frequency source in this case.
192
193- find out why frequency measurements always seem to start high and then slowly
194  drop
195

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