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c7303e4ac1
- cntr/README: description of the counter board and its application - cntr/fw/common/crc32.c: variant of CRC32-IEEE802.3 shared by firmware and measurement application - cntr/fw/cntr/ep0.c (my_setup), cntr/tools/cntr/cntr.c (get_sample): protect the counter value with a CRC and an one's complement copy - cntr/fw/include/cntr/ep0.h: oops, wasn't checked into repository - cntr/tools/cntr/cntr.c: added section titles - cntr/tools/cntr/cntr.c (measure): show communication statistics at the end - cntr/tools/cntr/cntr.c (measure, usage, main): new option -d to enable reporting of communication errors - cntr/tools/cntr/cntr.c (set_stop, measure): let user stop measurement with SIGINT - cntr/tools/cntr/cntr.c (measure): get multiple "first samples" and keep the one with the shortest round-trip time - cntr/tools/cntr/cntr.c (measure): changed unit "ppk" (1/1000) to percent (1/100) - cntr/tools/cntr/cntr.c (usage, main): command-line argument is now the accuracy goal, while the system clock deviation is set with the new option -c - TODO: some more things to do
135 lines
3.5 KiB
Plaintext
135 lines
3.5 KiB
Plaintext
General
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=======
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Things not done yet
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-------------------
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- document directory hierarchy
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- make sure all files have a copyright header or are listed in AUTHORS
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- connect all the bits and pieces of the build system
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- combine io-parts.h generation
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- combine "standard" EP0 commands, such as *_ID and *_BUILD
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- implement return to DFU in application's EP0 protocol
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- consider removing *_ID and using bcdDevice instead
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Bugs to fix
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-----------
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- builds fail if .version isn't there yet
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atrf
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====
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AT86RF230-based IEEE 802.15.4 transceiver. Two variantes: one to make a USB
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dongle for use with any Linux host, and one that connects with SPI directly
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inside a Ben.
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Things not done yet
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-------------------
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- define values for crystal load capacitors. Measurements with instruments not
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quite precise enough (+/- 100 ppm) for the task (+/- 40 ppm, preferably
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< +/- 10 ppm) suggest that we're about 300 ppm off with no capacitors at all
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and can only correct about 150 ppm with the internal trim capacitors.
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- examine spectrum around carrier frequency and first harmonic to look for
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obvious distortions. Vary transmit power.
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- measure throughput as a function of placement/distance, carrier frequency,
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and transmit power
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- atspi-txrx: suppport "extended mode" with IEEE 802.15.4 CSMA-CA for more
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realistic throughput figures
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- measure full spectrum (ideally up to 25 GHz, but just 2nd and 3rd harmonic
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will already tell most of the story) with calibrated antenna for FCC/ETSI
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compliance assessment. Vary transmit power.
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- use IEEE 802.15.4 stack from linux-zigbee
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- verify that the Ben can output an a) 16 MHz clock, and b) with +/- 40 ppm
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- replace discrete balun and filter with integrated solution, to reduce BOM
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size, maybe cost, insertion loss, and PCB space
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- check if we really need three DC blocking caps in the RF path
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- change layout of transceiver side of the board for placement inside Ben
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- define EMI filters for placement inside Ben
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- check USB standard for recommended USB dongle dimensions
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- change layout for straight USB dongle
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- generate proper BOM
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- implement sleep mode
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Bugs to fix
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-----------
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- two of my systems (tv and u1010) flat out refuse to talk to the board's USB
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application, but have no problem talking to its DFU boot loader. Very
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strange.
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- atrf vs. atspi naming is a bit confusing
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ccrf
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====
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Board similar to the atrf, but with the TI/Chipcon CC2520.
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cntr
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====
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Simple USB-based counter to measure a clock's long-time accuracy with
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arbitrarily high precision, by comparing it to an NTP time reference.
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Things not done yet
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-------------------
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- measure duty cycle
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- use the LED to display activity on clock input and duty cycle
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- consider using a comparator and a DAC to allow for programmable logic levels
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- evaluate termination resistance
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- document circuit design
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- record beats between 16 bit counter polls and use them for the estimate
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of lost cycles (2*1 is way too optimistic)
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- include system clock resolution in accuracy calculation
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- consider running shorter sliding windows to estimate drift
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- consider detecting unusual half-periods
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- consider using a reversed USB connector, to avoid having to cross D+/D- and,
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worse, VBUS and GND
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- test input performance by counting a source that emits a known number of
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cycles
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- consider using historical margins to sanity-check the current margin (if any
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old.max < curr.min or old.min > curr.max, we have a problem) and to further
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narrow the effective margin, thus achieving faster convergence. We would have
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to consider temperature drift of the frequency source in this case.
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