2 - chatted with Adrian some yesterday. He likes a Bosch pressure sensor that
3 is DK 828-1005-1-ND .. i2c output, similar range to our current part but
4 smaller, around $5 at our build quantities.
7 - looks like DK 644-1056-1-ND may be a good 32mhz rock choice for the cc1120
10 - thinking about what a second-generation TeleMetrum might be like
12 - board width sized to fit inside 38mm coupler .. say, 32mm wide
14 - ARM cpu w/USB interface
16 - STM32L151RBT6 DK 497-11193-ND 4.81 @ q100
18 - 128kx8 flash, 16kx8 RAM, 4kx8 EEPROM
19 - 64-LQFP with 51 i/o pins (48 or 100 pin variants)
20 - 20 x 12b ADC, 2 x 12b DAC
21 - 2 spi, 2 i2c, 3 usart, usb
22 - 1.8 or 3.3V, very low power
23 - needs 1-24 Mhz crystal
26 - SPI target with improved performance over cc1111
28 - 50mA typical power drain TX in 70cm band, 22mA receive
29 - wants 32 Mhz crystal
30 - maybe with a switched amplifier and preamp?
31 - can be used with the CC1190 on the 900mhz band (not useful)
33 - more than 2 pyro channels
35 - 10 screws are 25.86mm wide
36 - 12 screws are 30.94mm wide
38 - a better plan would be to put two screw strips back to
39 back aligned with the major axis of the board, so that
40 wires come out either side instead of to the rear?
42 - definitely want to support use of separate pyro battery,
43 need to think about the best way to do that.
46 can we get high dynamic firmware from Skytraq, or
47 do we need to change to a different vendor?
50 MS5607 .. I2C or SPI, 10 to 1200 mbar, 1uA, DFN-8'ish
53 1-axis high-G for motor characterization
54 MMA6556KWR2 .. SPI, 1 axis, +-120g, 7mA max, QFN-16
55 3-axis medium-G for orientation .. all are I2C or SPI
56 Bosch BMA250 16g, 8hz-1khz, 32lsb/g 3.07 q100
57 ST LIS331HH 24g, 50hz-1khz, 3mg/digit 4.89 q100
58 Analog ADXL345 16g, 6.25hz-3.2khz, 32lsb/g 5.88 q100
61 ST L3G3250A 2000dps, analog out (not really available?)
62 ST L3G4200D 2000dps, I2C or SPI, 1 ADC + mux
63 ITG-3200 2000dps, I2C only, 3 ADCs
64 ITG-3050 2000dps, I2C only, 3 ADCs, with low noise
65 and better sensitivity than the 3200?
67 Invensense also has an IMU-3000 that is like the above gyro
68 parts but can have a 3-axis accel as i2c slave and will do
69 the navigation computing. $12 vs $10 each. The MPU-6000/6050
70 is the holy grail, 3-axis gyro and accel on one chip that
71 outputs nav solutions... but it's not shipping yet.
74 - keithp points out that in the STM32L151 family, only the 100 pin versions
75 expose the second SPI port.
77 STM32L151VBT6 is DK 497-11195-ND, $5.38 @ q100
79 - 128kx8 flash, 16kx8 RAM, 4kx8 EEPROM
80 - 100-LQFP (14x14mm) with 83 i/o pins (48 or 64 pin variants)
81 - 24 x 12b ADC, 2 x 12b DAC
82 - 2 spi, 2 i2c, 3 usart, usb
83 - 1.8 or 3.3V, very low power
86 - decisions based on IRC conversation with keithp
87 + GPS on usart3 PC10/11 doesn't conflict with the serial bootloader
88 - pick either usart1 or usart2 on PD5/6 or PA9/10 for bootloader
89 - flash and companion can share an SPI, sensors need dedicated SPI
90 - use 3 screws for v_pyro, either jumper to tie to v_lipo or attach
91 separate battery .. plan to ship boards with the jumper installed
92 - 2 screws for power switch
93 - 6 pyro channels, 2 screws per channel = 12 screws
94 - 2-pin 2mm box connector for primary lipo
95 - same lipo charger as on lipocharger, set for 500ma charge rate
96 - include a screw attached to ground, easy attach for magnetic switch
97 - that makes 18 screws, use two 9's back to back
100 - STM32L151VBT6 Cortex-M3 SOC 5.39
101 - CC1120 digital radio spi2 6.60
102 - W25Q64BVZEIG 64Mbit flash spi2 2.06
105 - Freescale MMA6556KWR2 120g 1-axis accel spi1 5.00
106 - Bosch BMA250 16g 3-axis accel spi1 3.07
107 - Meas Spec MS5607 baro sensor spi1 6.35
108 - ITG-3200 2000 deg/sec 3-axis gyro i2c1 8.00
109 - SkyTraq Venus 638 GPS usart3 10.00
111 - companion port spi2
113 bootloader intf usart1
117 - tweak up the paste mask dimensions and so forth on BMA250.py, which is sort
118 of crude at the moment .. see page 68 of the BMA250 data sheet
121 - Eleazar Zuniga <ezuniga@taoglas.com> says in email of 28 Nov 2011 that we
122 should be able to use any of the pin or SMT patches other than the 35mm ones,
123 as long as we have ground plane under the patch itself that's as large as the
124 patch or bigger. I'm not sure I believe that, but adding an 0402 site to
125 ground for a tuning cap ala what the chip antenna docs call for might be a
126 reasonable thing to try?
131 12x12x4 mm, pin plus adhesive
132 gain towards zenith -0.5 dBic
135 15x15x4 mm, pin plus adhesive
139 18x18x2 mm, pin plus adhesive
140 gain towards zenith -0.5 dBic
143 18x18x4 mm, pin plus adhesive
144 gain towards zenith +3.5 dBic
145 $4.13 at q100 *** 50% the mass of 25mm
148 25x25x2 mm, pin plus adhesive
149 +2.0 dBic gain at zenith
152 25x25x4 mm, pin plus adhesive
153 gain towards zenith +3.5 dBic
156 surface-mount versions
160 -2.0 dBic at zenith, 4dB axial ratio, 6Mhz bandwidth
164 +1.0 dBic at zenith, 3dB axial ratio, 6Mhz bandwidth
168 +1.0 dBic at zenith, 4dB axial ratio, 5Mhz bandwidth
173 +2.0 dBic at zenith, 3dB axial ratio, 5Mhz bandwidth
175 By comparison the data on the chip antenna from Pulse Engineering we're
176 trying out on TeleTerra is:
179 required PCB surface around around 6x8 mm on a board edge
183 From all of this, GP.1575.18.4.A.02 would seem to be the clear winner. It
184 has 2.5 dB more gain than the chip antenna at the expense of a bit more
185 mass. However, if the chip antenna performance is "adequate", it saves
186 surface area, mass, and BOM cost.
189 - traded email with Invensense, their US distributor is cdiweb.com, they
190 have ITG-3200 in stock for $10 each and $8 in q100, and they have the new
191 IMU-6000 gyro+accel part for $15 each or $13 at q100.
193 http://www.cdiweb.com/Manufacturers/invensense
195 http://www.cdiweb.com/ProductDetail/ITG3200/405256
196 http://www.cdiweb.com/ProductDetail/MPU6000/420595
202 - STM32L151VBT6 Cortex-M3 SOC 5.39
203 - CC1120 digital radio spi2 6.60
204 - W25Q64BVZEIG 64Mbit flash spi2 2.06
207 - Freescale MMA6556KWR2 120g 1-axis accel spi1 5.00
208 - Meas Spec MS5607 baro sensor spi1 6.35
209 - IMU-6000 gyro+accel 13.00
210 - SkyTraq Venus 638 GPS usart3 10.00
211 - Honeywell HMC5883L magnetic sensor
213 - companion port spi2
215 bootloader intf usart1
219 - keithp reports what looks like RF getting into the SPI bus that the cc1120,
220 flash, and companion port are on. looking things over, we should:
222 - rotate the cc1120 180 degrees, bringing SPI off the northwest corner
223 and just dealing with the rework that will provoke on the UHF side
225 - add 330 ohm / 47pf snubbers on the source end of all SPI lines
227 - rework the SPI traces to put the SPI at one end as much as possible
229 - since MMA6556 remains unobtainium, moving to an Analog Devices part with
230 the 5V switcher may be necessary
232 - merge megaaccel content
234 - cut the big MicroMaTch down to just a 4-pin debug connector for STLINKv2?
236 - can we use the 64-pin version of the STM32L151?
237 - it looks like the answer is yes, but of course it would require a
238 massive re-routing of the board...
240 + move the MPU-6000 from I2C to SPI
242 + leave the mag sensor out
244 - that leaves nothing on I2C, but if we do use I2C, we need pull-ups!
248 - let's move to the u-blox MAX-6Q GPS on v0.2
249 http://www.u-blox.com/en/download/documents-a-resources/u-blox-6-gps-modules-resources.html