2 - for packaging a board to attach to a computer on the ground station side, I
3 have a Hammond box that looks good. Digi-Key part number HM380-ND, $2 in
8 - rewire P1_2 to be CS* for the SPI EEPROM instead of accel_st, ground ST pin
10 - USB connector shouldn't hang over the edge of the board
11 - reorder debug connector pinout to match what actually works with cp2103
12 - make USB connector a dual footprint to allow remoting using another connector
13 like the one we're using for serial port from the tiny series?
14 - change debug header to 5 pins so we can use one board to program another
15 by bringing a gpio over to drive reset? 5-pin connector from tiny series.
18 - Keith would like to use SPI to talk to TelePyro and TeleTerra boards, so
19 we're thinking of giving up an LED to get a second chip select line, and
20 reusing the existing SPI channel to the memory chip. Now, how do we do an
21 input interrupt from the PIC to flesh out a 7-pin connector?
23 rename net cs0 to cs_mem to reduce confusion
24 lose second LED attached to CPU, P1_1 becomes cs_ext
25 lose R12 since LED is no longer there
26 add J9, 7 pins, Molex pn footprint=530470710 digikey=WM1736-ND
27 define 'interrupt' as a new net ... now, how to hook it up?
29 So the problem is how to multiplex one cc1111 pin to be bidirectional. If
30 the cc1111 asserts that pin, we need the PIC cs input to go low. If the
31 cc1111 isn't asserting it (switched to input), then we want the state of
32 the PIC interrupt output to be reflected there. But how can we drive the
33 cc1111 input while simultaneously knowing when it's being asserted as an
34 output? Doesn't seem possible. How does the Dallas 1-wire stuff work?
37 - based on experiences and discussion at Mile High Mayhem, here's what we
38 think we want to do at the schematic level:
40 + known changes for two cuts and jumps and two added resistors
41 + lose the temp sensor
43 + lose the 4-pin serial port connector
44 + change the debug connector to 4 pins 1.25mm ala deleted serial port
45 + add 7-pin 1.25mm connector that extends SPI for TT/TP and doubles
46 as debug control port for flashing another board with 7-4 pin cable
47 gnd, v_lipo, mo0, mi0, c0, cs1 (ex temp), irq1 (ex beeper)
49 + wire v_lipo to the igniter fets directly
50 + include a connector for an external pyro battery
51 + add one or two 1206 caps between +3.3V and gnd to ballast against
52 power switch bounce and/or brown-out on igniter firing:
54 DK 490-4512-1-ND is a 100uF 1206 part, 1.32 in 100 pieces
55 DK 445-1428-1-ND is a 47uF 1206 part, 0.91 in 100 pieces
57 + add MN5010HS GPS chip, chip antenna, and associated circuitry
59 BAS16 is DK BAS16LT3GOSCT-ND, SOT-23-3, 0.05 in 100 pieces
60 BSS138 is DK BSS138LT1GOSCT-ND, SOT-23-3, 0.14 in 100 pieces
61 33nF cap for antenna is DK 490-1315-1-ND, 0402, 0.03 in 100s
64 - after more thinking about this, I want to add the serial connector back in
65 but as an optionally loaded part ... if I can make it fit.
67 - can I put the GPS chip antenna on the board *and* allow for an SMA or other
68 connector if we want it off-board?
70 - changing the memory part from the SOIJ8 to the DFN8 would save about 2mm
71 in width, but that doesn't really help.
72 - changing the 5V switcher from S8 to MS8 takes us from 5 tall to 3 tall, but
73 costs $0.30 more per piece and isn't stocked by Digikey. Not worth it?
75 - noticed the NXP SC18IS600, which is an SPI slave to I2C master interface
76 with a few GPIO lines... mate that with an HMC5843, which is a 3-axis
77 magnetic sensor, and we might have another interesting companion board for TM
83 - add serial connector back to schematic as optionally loaded part
84 - move USB connector on PCB layout 80 mils in from board edge
85 - move yellow LED and passives closer to LiPo connector
86 + create PCB footprint for the GPS module
87 + create PCB footprint for the GPS antenna
91 - flew lots of stuff last weekend at O'fest. 100g accel worked ok in G-Spot,
92 broke beeper presumably on landing with tangled chute. board seems ok
93 otherwise, need to verify that baro sensor is still ok.
95 - put out sample requests for gps passive patches from 3 vendors
97 - when adding GPS, let's plan for passive patch loaded on the back of the
98 board, plus a U.FL connector loaded on the top of the board with DC bias feed
99 to support external active antennas. This probably means passive patch
100 direct to gps chip, then a dc blocking cap, a chip inductor for dc bias
101 injection, and the connector. A suitable connector is:
103 WM5587CT-ND Molex 73412-0110 0.70 in single quantity
105 Keith found gps active antennas with cable to U.FL connectors and Molex sells
106 cables with U.FL to bare leads, so this should cover the bases.
108 - TelePyro doesn't really need a CPU. How about an SPI to I2C converter chip
109 with GPIO lines and an I2C ADC chip? Cheaper and easier than a PIC?
111 PIC16F882 in SSOP-28 is $2.10 per, 1.41 @ 25 units
112 -- PIC16F883 is $2.12, PIC16F886 is $2.32, have better memories
113 CP2120 in QFN-20 is $2.41 per, 2.27 @ 25 units
115 The Silabs CP2120 has 8 gpio lines but is only available in QFN20. The NXP
116 part I discovered earlier, the SC18IS600, has 4 full gpio lines and 2 lame-o
117 pins, but is available in a hand-solderable version. Add in a Maxim ADC,
118 and something like this emerges:
120 DigiKey 568-3232-5-ND NXP SC18IS600IPW,112 2.25
121 DigiKey MAX11603EEE+-ND Maxim MAX11603EEE+ 4.00
122 Mouser 595-CD4508BM TI CD4508BM 1.70
124 The 4508 has separate reset inputs and latch controls for each 4-bit latch.
125 The reset forces all outputs low, and the reset is an active-high input.
127 The NXP part has an active-low reset input, with 10-30k internal pullup.
129 The ADC has no distinct reset input.
131 A suitable SOT-23-5 reset controller is the MCP1319MT-29LE... it has a master
132 reset input we can ignore, and both active high and active low reset outputs.
134 DigiKey MCP1319MT-29LE/OTCT-ND 0.70
136 This plus 8 copies of the pyro circuit on TM (FET and 4 resistors) and we're
139 Wonder if there are resistor networks it'd be worth trying to use to ease
140 component placement? Yes... these are 8 x 0402, more or less:
142 100 ohm 741X163101JPCT-ND 0.16
143 10k 741X163103JPCT-ND 0.16
147 - another way to think about all this is that I could panelize a set of boards
148 all done in 2 layers, then treat that as a sub-panel I put N copies down of
149 to fill up a 33each.com max panel size.
152 - move to AT45DB161D 16-megabit SPI "DataFlash" EEPROM from Atmel?
153 AT45DB161D-SU-ND in SOIC-8 for $2.26 each
154 appears to compare favorably against $4.40 for current 128kx8 part
155 minor concern about write power, but probably red herring
158 - looking at LiPo charger alternatives
160 MAX8808 DFN8, not carried by DK
161 MAX8814 DFN8, not carried by DK
163 LTC4095 DFN8, LTC4095EDC#TRMPBFCT-ND 2.91 2.34@100
164 950mA, resistor current set, rate limit input, suspend input,
165 NTC thermal control option, smart CHRG led with 4 states
166 LTC4065 DFN6, LTC4065EDC#TRMPBFCT-ND 2.77 2.23@100
167 750mA, resistor current set, CHRG led, enable input
168 LTC4065A DFN6, LTC4065AEDC#TRMPBFCT-ND 2.77 2.23@100
169 750mA, resistor current set, CHRG led, supply present out
171 MCP73811 SOT23-5, MCP73811T-420I/OTCT-ND 0.63@1 0.39@100
172 input selects 85 vs 450mA charge current
174 MCP73837 DFN10, MCP73837T-FCI/MFCT-ND 1.37@1 0.85@100
175 usb rate select, power good output, dual inputs, dual status
177 LX2206 DFN10, LX2206CT-ND 2.68@1 2.01@100
178 rate select, power good output... needs more passives?
181 dual input, dual rate, two status outputs .. not obvious win
183 MCP73855 DFN10, MCP73855T-I/MFCT-ND 1.85@1 1.18@100
184 see Microchip app note 971
187 Talking to Keith, there's no reason we couldn't use an 8-pin PIC to augment
188 a standalone LiPo charger, implementing a timer after vusb application
189 before switching the regulator to high current, to allow the cc1111 time to
190 finish the USB bus negotiation phase. We could also monitor various state
191 bits and multiplex signaling onto one LED. A combo like the MCP73837 plus
192 a PIC10F206 or 220 would net under $1.50 at 100 pieces and be pretty
193 powerful. Since the PIC has avilable weak pull-ups on the gpio lines, the
194 open-drain state outputs from the regulator don't need resistors to be read.
197 - v1.0 and v1.1 boards have a minor error in that the v_lipo sampling resistors
198 are on "the wrong side of the cut" if you try to use a separate pyro battery.
199 The workaround is to cut that trace and put in a jumper, which pretty much
200 requires "return to Bdale for rework". We should fix this for a future PCB
204 - chatted with Adrian some yesterday. He likes a Bosch pressure sensor that
205 is DK 828-1005-1-ND .. i2c output, similar range to our current part but
206 smaller, around $5 at our build quantities.
209 - the Johanson balun/filter for 70cm use with cc1111 is DK 712-1540-1-ND
210 uses less PCB area, but lower performance than the discrete approach
213 - noodling over TM v2.0 .. baro sensor will be hard to handle on cc1111. So,
214 how about 48-pin version of STM32L, cc110L radio, ms5607 and MMA665X accel.
215 Move to the faster lipo charger, too.
216 radio / flash on spi2, sensors on spi1, baro on spi1 alternate pins
219 - serious stab at what should be on TeleMetrum v2 .. used cc115L section from
220 TeleGPS since I didn't have a cc110L data sheet on the plane .. hope it's
221 similar .. need to update to transceiver, not just transmitter!
projects / hw / telemetrum / blob