2011.11.23
- decisions based on IRC conversation with keithp
- - GPS on usart3 PC10/11 doesn't conflict with the serial bootloader
+ + GPS on usart3 PC10/11 doesn't conflict with the serial bootloader
- pick either usart1 or usart2 on PD5/6 or PA9/10 for bootloader
- flash and companion can share an SPI, sensors need dedicated SPI
- use 3 screws for v_pyro, either jumper to tie to v_lipo or attach
- include a screw attached to ground, easy attach for magnetic switch
- that makes 18 screws, use two 9's back to back
- - silicon
- - STM32L151VBT6 Cortex-M3 SOC
- - CC1120 digital radio spi2
- - W25Q64BVZEIG 64Mbit flash spi2
+ - silicon q100 $
+ - STM32L151VBT6 Cortex-M3 SOC 5.39
+ - CC1120 digital radio spi2 6.60
+ - W25Q64BVZEIG 64Mbit flash spi2 2.06
- sensors
- - Freescale MMA6556KWR2 120g 1-axis accel spi1
- - Bosch BMA250 16g 3-axis accel spi1
- - Meas Spec MS5607 baro sensor spi1
- - ITG-3200 2000 deg/sec 3-axis gyro i2c1
- - SkyTraq Venus 638 GPS usart3
+ - Freescale MMA6556KWR2 120g 1-axis accel spi1 5.00
+ - Bosch BMA250 16g 3-axis accel spi1 3.07
+ - Meas Spec MS5607 baro sensor spi1 6.35
+ - ITG-3200 2000 deg/sec 3-axis gyro i2c1 8.00
+ - SkyTraq Venus 638 GPS usart3 10.00
- companion port spi2
i2c2
bootloader intf usart1
usart2
+To Do
+- tweak up the paste mask dimensions and so forth on BMA250.py, which is sort
+ of crude at the moment .. see page 68 of the BMA250 data sheet
+
+2011.11.29
+- Eleazar Zuniga <ezuniga@taoglas.com> says in email of 28 Nov 2011 that we
+ should be able to use any of the pin or SMT patches other than the 35mm ones,
+ as long as we have ground plane under the patch itself that's as large as the
+ patch or bigger. I'm not sure I believe that, but adding an 0402 site to
+ ground for a tuning cap ala what the chip antenna docs call for might be a
+ reasonable thing to try?
+
+ pinned versions
+
+ GP.1575.12.4.A.02
+ 12x12x4 mm, pin plus adhesive
+ gain towards zenith -0.5 dBic
+
+ GP.1575.15.4.B.02
+ 15x15x4 mm, pin plus adhesive
+ 1.0 dBic at zenith
+
+ GP.1575.18.2.A.02
+ 18x18x2 mm, pin plus adhesive
+ gain towards zenith -0.5 dBic
+
+ GP.1575.18.4.A.02
+ 18x18x4 mm, pin plus adhesive
+ gain towards zenith +3.5 dBic
+ $4.13 at q100 *** 50% the mass of 25mm
+
+ GP.1575.25.2.A.02
+ 25x25x2 mm, pin plus adhesive
+ +2.0 dBic gain at zenith
+
+ GP.1575.25.4.A.02
+ 25x25x4 mm, pin plus adhesive
+ gain towards zenith +3.5 dBic
+ $4.05 at q100
+
+ surface-mount versions
+
+ SGP.1575.12.4.A.02
+ 12x12x4.5 mm
+ -2.0 dBic at zenith, 4dB axial ratio, 6Mhz bandwidth
+
+ SGP.1575.15.4.A.02
+ 15x15x4.5 mm
+ +1.0 dBic at zenith, 3dB axial ratio, 6Mhz bandwidth
+
+ SGP.1575.18.4.C.02
+ 18x18x4.5 mm
+ +1.0 dBic at zenith, 4dB axial ratio, 5Mhz bandwidth
+ $4.94 at q100
+
+ SGP.1575.25.4.C.02
+ 25x25x4.5 mm
+ +2.0 dBic at zenith, 3dB axial ratio, 5Mhz bandwidth
+
+ By comparison the data on the chip antenna from Pulse Engineering we're
+ trying out on TeleTerra is:
+
+ W3011A
+ required PCB surface around around 6x8 mm on a board edge
+ +1.0 dBic peak
+ $1.28 at q100
+
+ From all of this, GP.1575.18.4.A.02 would seem to be the clear winner. It
+ has 2.5 dB more gain than the chip antenna at the expense of a bit more
+ mass. However, if the chip antenna performance is "adequate", it saves
+ surface area, mass, and BOM cost.
+
+2011.12.01
+- traded email with Invensense, their US distributor is cdiweb.com, they
+ have ITG-3200 in stock for $10 each and $8 in q100, and they have the new
+ IMU-6000 gyro+accel part for $15 each or $13 at q100.
+
+ http://www.cdiweb.com/Manufacturers/invensense
+
+ http://www.cdiweb.com/ProductDetail/ITG3200/405256
+ http://www.cdiweb.com/ProductDetail/MPU6000/420595
+
+2012.02.06
+- so where are we...
+
+ - silicon q100 $
+ - STM32L151VBT6 Cortex-M3 SOC 5.39
+ - CC1120 digital radio spi2 6.60
+ - W25Q64BVZEIG 64Mbit flash spi2 2.06
+
+ - sensors
+ - Freescale MMA6556KWR2 120g 1-axis accel spi1 5.00
+ - Meas Spec MS5607 baro sensor spi1 6.35
+ - IMU-6000 gyro+accel 13.00
+ - SkyTraq Venus 638 GPS usart3 10.00
+ - Honeywell HMC5883L magnetic sensor
+
+ - companion port spi2
+ i2c2
+ bootloader intf usart1
+ usart2
+
+2012.06.17
+- keithp reports what looks like RF getting into the SPI bus that the cc1120,
+ flash, and companion port are on. looking things over, we should:
+
+ - rotate the cc1120 180 degrees, bringing SPI off the northwest corner
+ and just dealing with the rework that will provoke on the UHF side
+
+ - add 330 ohm / 47pf snubbers on the source end of all SPI lines
+
+ - rework the SPI traces to put the SPI at one end as much as possible
+
+- since MMA6556 remains unobtainium, moving to an Analog Devices part with
+ the 5V switcher may be necessary
+ + elide MMA6556
+ - merge megaaccel content
+
+- cut the big MicroMaTch down to just a 4-pin debug connector for STLINKv2?
+
+- can we use the 64-pin version of the STM32L151?
+ - it looks like the answer is yes, but of course it would require a
+ massive re-routing of the board...
+
++ move the MPU-6000 from I2C to SPI
+
++ leave the mag sensor out
+
+- that leaves nothing on I2C, but if we do use I2C, we need pull-ups!
+
+
+2012.06.30
+- let's move to the u-blox MAX-6Q GPS on v0.2
+ http://www.u-blox.com/en/download/documents-a-resources/u-blox-6-gps-modules-resources.html
projects / hw / telemega / blobdiff