+++ /dev/null
-2008.12.21
-- for packaging a board to attach to a computer on the ground station side, I
- have a Hammond box that looks good. Digi-Key part number HM380-ND, $2 in
- singles.
-
-2009.03.16
-
-- rewire P1_2 to be CS* for the SPI EEPROM instead of accel_st, ground ST pin
-
-- USB connector shouldn't hang over the edge of the board
-- reorder debug connector pinout to match what actually works with cp2103
-- make USB connector a dual footprint to allow remoting using another connector
- like the one we're using for serial port from the tiny series?
-- change debug header to 5 pins so we can use one board to program another
- by bringing a gpio over to drive reset? 5-pin connector from tiny series.
-
-2009.04.21
-- Keith would like to use SPI to talk to TelePyro and TeleTerra boards, so
- we're thinking of giving up an LED to get a second chip select line, and
- reusing the existing SPI channel to the memory chip. Now, how do we do an
- input interrupt from the PIC to flesh out a 7-pin connector?
-
- rename net cs0 to cs_mem to reduce confusion
- lose second LED attached to CPU, P1_1 becomes cs_ext
- lose R12 since LED is no longer there
- add J9, 7 pins, Molex pn footprint=530470710 digikey=WM1736-ND
- define 'interrupt' as a new net ... now, how to hook it up?
-
- So the problem is how to multiplex one cc1111 pin to be bidirectional. If
- the cc1111 asserts that pin, we need the PIC cs input to go low. If the
- cc1111 isn't asserting it (switched to input), then we want the state of
- the PIC interrupt output to be reflected there. But how can we drive the
- cc1111 input while simultaneously knowing when it's being asserted as an
- output? Doesn't seem possible. How does the Dallas 1-wire stuff work?
-
-2009.05.27
-- based on experiences and discussion at Mile High Mayhem, here's what we
- think we want to do at the schematic level:
-
- + known changes for two cuts and jumps and two added resistors
- + lose the temp sensor
- + lose the beeper
- + lose the 4-pin serial port connector
- + change the debug connector to 4 pins 1.25mm ala deleted serial port
- + add 7-pin 1.25mm connector that extends SPI for TT/TP and doubles
- as debug control port for flashing another board with 7-4 pin cable
- gnd, v_lipo, mo0, mi0, c0, cs1 (ex temp), irq1 (ex beeper)
- + lose the 1000uF cap
- + wire v_lipo to the igniter fets directly
- + include a connector for an external pyro battery
- + add one or two 1206 caps between +3.3V and gnd to ballast against
- power switch bounce and/or brown-out on igniter firing:
-
- DK 490-4512-1-ND is a 100uF 1206 part, 1.32 in 100 pieces
- DK 445-1428-1-ND is a 47uF 1206 part, 0.91 in 100 pieces
-
- + add MN5010HS GPS chip, chip antenna, and associated circuitry
-
- BAS16 is DK BAS16LT3GOSCT-ND, SOT-23-3, 0.05 in 100 pieces
- BSS138 is DK BSS138LT1GOSCT-ND, SOT-23-3, 0.14 in 100 pieces
- 33nF cap for antenna is DK 490-1315-1-ND, 0402, 0.03 in 100s
-
-2009.06.01
-- after more thinking about this, I want to add the serial connector back in
- but as an optionally loaded part ... if I can make it fit.
-
-- can I put the GPS chip antenna on the board *and* allow for an SMA or other
- connector if we want it off-board?
-
-- changing the memory part from the SOIJ8 to the DFN8 would save about 2mm
- in width, but that doesn't really help.
-- changing the 5V switcher from S8 to MS8 takes us from 5 tall to 3 tall, but
- costs $0.30 more per piece and isn't stocked by Digikey. Not worth it?
-
-- noticed the NXP SC18IS600, which is an SPI slave to I2C master interface
- with a few GPIO lines... mate that with an HMC5843, which is a 3-axis
- magnetic sensor, and we might have another interesting companion board for TM
-
-
-
-- To Do List
-
- - add serial connector back to schematic as optionally loaded part
- - move USB connector on PCB layout 80 mils in from board edge
- - move yellow LED and passives closer to LiPo connector
- + create PCB footprint for the GPS module
- + create PCB footprint for the GPS antenna
-
-
-2009.10.09
-- flew lots of stuff last weekend at O'fest. 100g accel worked ok in G-Spot,
- broke beeper presumably on landing with tangled chute. board seems ok
- otherwise, need to verify that baro sensor is still ok.
-
-- put out sample requests for gps passive patches from 3 vendors
-
-- when adding GPS, let's plan for passive patch loaded on the back of the
- board, plus a U.FL connector loaded on the top of the board with DC bias feed
- to support external active antennas. This probably means passive patch
- direct to gps chip, then a dc blocking cap, a chip inductor for dc bias
- injection, and the connector. A suitable connector is:
-
- WM5587CT-ND Molex 73412-0110 0.70 in single quantity
-
- Keith found gps active antennas with cable to U.FL connectors and Molex sells
- cables with U.FL to bare leads, so this should cover the bases.
-
-- TelePyro doesn't really need a CPU. How about an SPI to I2C converter chip
- with GPIO lines and an I2C ADC chip? Cheaper and easier than a PIC?
-
- PIC16F882 in SSOP-28 is $2.10 per, 1.41 @ 25 units
- -- PIC16F883 is $2.12, PIC16F886 is $2.32, have better memories
- CP2120 in QFN-20 is $2.41 per, 2.27 @ 25 units
-
- The Silabs CP2120 has 8 gpio lines but is only available in QFN20. The NXP
- part I discovered earlier, the SC18IS600, has 4 full gpio lines and 2 lame-o
- pins, but is available in a hand-solderable version. Add in a Maxim ADC,
- and something like this emerges:
-
- DigiKey 568-3232-5-ND NXP SC18IS600IPW,112 2.25
- DigiKey MAX11603EEE+-ND Maxim MAX11603EEE+ 4.00
- Mouser 595-CD4508BM TI CD4508BM 1.70
-
- The 4508 has separate reset inputs and latch controls for each 4-bit latch.
- The reset forces all outputs low, and the reset is an active-high input.
-
- The NXP part has an active-low reset input, with 10-30k internal pullup.
-
- The ADC has no distinct reset input.
-
- A suitable SOT-23-5 reset controller is the MCP1319MT-29LE... it has a master
- reset input we can ignore, and both active high and active low reset outputs.
-
- DigiKey MCP1319MT-29LE/OTCT-ND 0.70
-
- This plus 8 copies of the pyro circuit on TM (FET and 4 resistors) and we're
- good to go.
-
- Wonder if there are resistor networks it'd be worth trying to use to ease
- component placement? Yes... these are 8 x 0402, more or less:
-
- 100 ohm 741X163101JPCT-ND 0.16
- 10k 741X163103JPCT-ND 0.16
- 27k Y1273CT-ND 0.18
- 100k Y1104CT-ND 0.18
-
-- another way to think about all this is that I could panelize a set of boards
- all done in 2 layers, then treat that as a sub-panel I put N copies down of
- to fill up a 33each.com max panel size.
-
-2009.10.16
-- move to AT45DB161D 16-megabit SPI "DataFlash" EEPROM from Atmel?
- AT45DB161D-SU-ND in SOIC-8 for $2.26 each
- appears to compare favorably against $4.40 for current 128kx8 part
- minor concern about write power, but probably red herring
-
-2010.02.08
-- looking at LiPo charger alternatives
-
- MAX8808 DFN8, not carried by DK
- MAX8814 DFN8, not carried by DK
-
- LTC4095 DFN8, LTC4095EDC#TRMPBFCT-ND 2.91 2.34@100
- 950mA, resistor current set, rate limit input, suspend input,
- NTC thermal control option, smart CHRG led with 4 states
- LTC4065 DFN6, LTC4065EDC#TRMPBFCT-ND 2.77 2.23@100
- 750mA, resistor current set, CHRG led, enable input
- LTC4065A DFN6, LTC4065AEDC#TRMPBFCT-ND 2.77 2.23@100
- 750mA, resistor current set, CHRG led, supply present out
-
- MCP73811 SOT23-5, MCP73811T-420I/OTCT-ND 0.63@1 0.39@100
- input selects 85 vs 450mA charge current
-
- MCP73837 DFN10, MCP73837T-FCI/MFCT-ND 1.37@1 0.85@100
- usb rate select, power good output, dual inputs, dual status
-
- LX2206 DFN10, LX2206CT-ND 2.68@1 2.01@100
- rate select, power good output... needs more passives?
-
- LM3658 DFN10,
- dual input, dual rate, two status outputs .. not obvious win
-
- MCP73855 DFN10, MCP73855T-I/MFCT-ND 1.85@1 1.18@100
- see Microchip app note 971
-
-
- Talking to Keith, there's no reason we couldn't use an 8-pin PIC to augment
- a standalone LiPo charger, implementing a timer after vusb application
- before switching the regulator to high current, to allow the cc1111 time to
- finish the USB bus negotiation phase. We could also monitor various state
- bits and multiplex signaling onto one LED. A combo like the MCP73837 plus
- a PIC10F206 or 220 would net under $1.50 at 100 pieces and be pretty
- powerful. Since the PIC has avilable weak pull-ups on the gpio lines, the
- open-drain state outputs from the regulator don't need resistors to be read.
-
-2011.01.17
-- v1.0 and v1.1 boards have a minor error in that the v_lipo sampling resistors
- are on "the wrong side of the cut" if you try to use a separate pyro battery.
- The workaround is to cut that trace and put in a jumper, which pretty much
- requires "return to Bdale for rework". We should fix this for a future PCB
- revision.
-
-2011.09.12
-- chatted with Adrian some yesterday. He likes a Bosch pressure sensor that
- is DK 828-1005-1-ND .. i2c output, similar range to our current part but
- smaller, around $5 at our build quantities.
-
-2011.12.10
-- the Johanson balun/filter for 70cm use with cc1111 is DK 712-1540-1-ND
- uses less PCB area, but lower performance than the discrete approach
-
-2013.01.04
-- noodling over TM v2.0 .. baro sensor will be hard to handle on cc1111. So,
- how about 48-pin version of STM32L, cc110L radio, ms5607 and MMA665X accel.
- Move to the faster lipo charger, too.
- radio / flash on spi2, sensors on spi1, baro on spi1 alternate pins
-
-2013.05.02
-- serious stab at what should be on TeleMetrum v2 .. used cc115L section from
- TeleGPS since I didn't have a cc110L data sheet on the plane .. hope it's
- similar .. need to update to transceiver, not just transmitter!
-
projects / hw / telemetrum / blobdiff