ECEDesignNotes¶
Design notes for the ScoutFly. Will not be in any real order or organisation. Just a dump of ideas as they come along. Contact kwoo@ to discuss things. Try not to modify this unless you have been given permission to.
Note: Alot of this documentation is out of date due to the switch to using the gumstix. Please verify that it is correct before proceeding.
Bootstrapping¶
- If GPI_01 determines what device to boot from
- if high, boot from UART5
- if low, boot from (in this order) SSP0 -> EMC (CS0) -> NAND
UART¶
| ARM UART | Connection | Notes |
| 1 | AVR UART 0 | Size level shifters for .5Mbit/s max |
| 2 | XBee | |
| 3 | BOM | |
| 4 | ||
| 5 | FTDI USB | For Booting over serial, OS bootstrapping |
| 6 | ||
| 7 |
I2C¶
- Level shifter: http://www.standardics.nxp.com/support/documents/i2c/pdf/an97055.pdf
**used an IC because it was cheaper
Debouncing¶
Followed the usual guide: http://embedded.com/showarticle.jhtm?articleid=18902552
Power¶
Power Supplies¶
| Source | Charge | Logic Power Polarity | Powers Motors |
| USB | no | 1 | no |
| charging station contacts (12V) | yes | 2 | no |
| Battery (dual cell lion) | n/a | 3 | yes |
Reverse polarity problems¶
- We only need to worry about problems coming in on the battery
- TI App Note
- Use the FET method, I don't think it matters which one we use though (NFET vs PFET)
- Maxim App Note
Push Button On¶
- Separate chip to handle it
- LTC2952
- Informs the processor of shutdown starting and allows processor to control when it happens
- Integrated Power OR (see below)
Power Controllers¶
- We need to select which source to use when multiple are plugged in. We can use a PowerPath IC to handle this.
- Thinking of LTC4412
- Single source, the primary isn't present the secondary will kick in
- or LTC4416
- Dual source, if the primary isn't present the secondary will be switched to
- The LTC4412 requires us to use one less FETs but the switch time is slower (175us vs 60us)
- LTC1473
- Dual source, but allows us to use a DC bypass. This could save us a chip
- We need logic to decide which battery to take though
- Thinking of LTC4412
- LTC4412 has the least need for extra components and is cheaper per chip. We need the same amount of chips regardless of which we choose.
- We only need to do 1 level now. We get an extra level from the LTC2952
Charging¶
- Max 745
- Expensive...$8.76 in our quantities
- Can do 1-4 cell batteries, 4A max, less external components
- The 2A charging requirement took out most of the chips that can do 2+ cells
- This actually can do thermal shutdown if the battery OR itself gets too hot
- Less external components than the cheaper chips
Power Domains¶
| Voltage | Load | Regulator | What's on it |
| 7V | 3.5A (when all 5 motors stall) | Unregged | Steppers, drive motors |
| 5V | 77.2mA | LT3507 | AVR, Quadrature Encoders, Sonar, Cliff Sensor, Motor Drivers |
| 3.3V | 325mA | LT3507 | XBee, VDD_AD (A2D convertor, note we need a lowpass filter, LC), VDD_IOB, VDD_IOD (these two are for ethernet), Accelerometer, Gyro, Orbs |
| 1.8V | 40mA | LT3507 | DDR SDRAM, NAND FLASH, VDD_IOC (this is the flash pins), VDD_EMC (sdram pins) |
| 1.2V | 80mA | LT3507 | ARM Core (VDD_CORE), ARM Core Fixed (VDD_COREFXD), VDD_PLL297, VDD_PLLHCLK, VDD_PLLUSB, VDD_FUSE, VDD_RTC, VDD_RTCCORE, VDD_RTCOSC |
VDD_IOA, VDD_IOB, VDD_IOD (1.7 - 3.6), these need to be set to whatever we're interfacing to
The current load numbers are probably undershooting so add some factors of safety because I did a lot of rounding and guessing. Note that these current numbers don't reflect the draw of external components. Most notably support chips such as the RAM, FLASH, micro SD, PHY, etc. They will probably be the heaviest draw on the 3.3V lines though.
Regulators¶
- LT3507 - Triple buck converter, adjustable, 1 LDO
- Can use the actual outputs to drive 5V, 3.3V, and 1.2V
Motors¶
- 700mA each, current limited
- use a current limiting circuit
ESD¶
- http://electronicdesign.com/Articles/Index.cfm?AD=1&AD=1&ArticleID=3727
- Vishay app notes on TVS
- An Overview of ESD Protection Devices
SD Card Interface¶
Stolen from: http://www.interfacebus.com/Secure_Digital_Card_Pinout.html
| PIN# | Pin Name |
| 1 | Data 2 |
| 2 | Card Detect / Data 3 |
| 3 | Command |
| 4 | Vdd (2.7V - 3.6V) |
| 5 | Clk |
| 6 | GND |
| 7 | Data 0 |
| 8 | Data 1 |
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
You need to initiate the card through several steps. Here is the specification: http://www.sdcard.org/developers/tech/sdcard/pls/Simplified_Physical_Layer_Spec.pdf
Parts list¶
New for v2 Parts¶
| Linear LTC3633 | Dual Buck Converter | We only need 3.3V and 5V now, this does 3A on each channel with integrated fets. Just need inductors and some caps | TSSOP-28 | newark | datasheet |
| TI TXB0108 | Hex Level shifter, bi directional | For 1.8 to 3.3 or 3.3 to 5.5 | TSSOP-20 | digikey" | datasheet |
| Worth 748421245 | Balun | For the wireless antennae, be careful with layout | ??? | datasheet | digikey |
| Microchip TC1015-1.8VCT713 | 1.8V Linear Regulator | 3.3V to 1.8V for levelshifting to the ARM | SOT23-5 | datasheet" | digikey |
| TDK RLF7030T-1R0N6R4 | 1uH Inductor | For the 3.3V switching regulator | n/a | datasheet | digikey |
| TDK RRLF7030T-1R5N6R1 | 1.5uH Inductor | For the 5V switching regulator | n/a | datasheet | digikey |
| TI SN74LVC1G11 | 3 input AND Gate | For AVR reset since we have 3 reset sources. Eliminates the need to use a bunch of resistor to prevent drive fights and marginally making it in terms of the correct voltages to turn off | datasheet | digikey | |
| Panasonic PCE3294CT-ND | 47uF AlElec Cap | Input caps for the regulator 5/3.3 Panasonic size "C" | datasheet | digikey" | |
| Cap 22uF | 1210, low esr, for output cap for regulator | http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=445-3949-1-ND | |||
| Atmel ATMEGA128RFA1 | AVR Micro with RF component | Stupid atmel keeps pushing the release date back | 64qfn | "digikey": | datasheet |
| Alegro A3967 | Stepper Controller | The last one only operates at a 8V min, this operates at 4.5V min for the supply | 24-SOIC | "digikey": | datasheet |
| Part | Function | Notes | Package | Digikey | Datasheet |
| MAX745 | 1-4 Cell Lith Ion Charger | Does 2A+ that we wanted, most can only handle 1.5A for charging. A little expensive but allows a wide variety of input voltages and is flexible if our power situation changes | 20-SSOP | digikey | datasheet |
| LT3507 | Logic Power Supply | Triple buck converter with a built in LDO. We need one more LDO to handle the 5th voltage domain we have. This gives us a lot of power for the accessories...likes 1-2A+ | 38-QFN | digikey | datasheet |
| LTC2952 | Push Button Controller | Initiates boot up and shut down via push button, has a power-path integrated for ORing of power supplies to be used with LTC4412 | 20-QFN | digikey | datasheet |
| LTC4412 | Power OR Controller | We use these to prioritise the different power inputs. We cascade them to form a tree | TSOT-23-6 | digikey | datasheet |
| Vishay/Siliconix SI5401DC-T1-E3 | P-Channel MOSFET, 20V, 5.2A | for the power-channel stuff, takes our max power consumption | 1206-8 ChipFET | digikey | datasheet |
| IR IRF7303TRPBF | Dual NFET, 30V, 4.9A | For the battery charger | 8-SOIC | digikey | datasheet |
| Fairchild MBRS340 | Schottky Diode 40V, 3A | For the MAX745 charger, LT3507 diodes | DO-214AB | digikey | datasheet |
| Micro Comercial Co 1N4148W-TP | Switch Diode 100V, 150mA | For LT3507/MAX745 Boost diode | SOD-123 | digikey | datasheet |
| National DP83848JSQ/NOPB | Ethernet PHY | Ethernet PHY -> MII/RMII Interface | 40-LLP | digikey | datasheet |
| Maxim DS2786G+ | Lithion Gas Gauge | Need to do that nasty hack | 10-TDFN | digikey | datasheet |
| Coiltronics DR74-4R7-R | 4.7uH, 3.34A Max Inductor | Shielded, 25mOhm DCR, 20% Tolerance | N/A | digikey | datasheet |
| Taiyo Yuden NR6045T3R0N | 3uH, 5A Inductor | Shielded, 24mOhm DCR, 30% Tolerance | N/A | digikey | datasheet |
| Coiltronics DR125-220-R | 22uH, 3.7A Max Inductor | Shielded, 39.6mOhm DCR, 20% Tolerance | N/A | digikey | datasheet |
| Pulse J00-0064NL | RJ45 Jack with Magnetics | Smaller than the other one by a good amount but lacks LEDs | RJ45 | digikey | datasheet |
| Hirose UX60-MB-5S8 | USB Mini-B Connector, Female | For FTDI | N/A | digikey | datasheet |
| Steward MI0805K400R-10 | Ferrite Bead | For USB 5V on FTDI | 0805 | digikey | datasheet |
| AVX Corp KC3225A50.0000C30E00 | 50MHz, 3.3V oscillator | For Ethernet PHY, using RMII so we needed a clock 2x as fast as when we used MII | N/A | digikey | datasheet |
| ECS ECS-.327-12.5-34B | 32.768kHz RTC Crystal | For the RTC, smaller than the old one | N/A | digikey | datasheet |
| NDK NX3225SA-16.000000MHZ | Crystal, 16MHz | ATMega128 Clock | N/A | digikey | datasheet |
| Bourns Inc MF-SM200-2 | Resettable Fuse | Blows over 4A | N/A | digikey | datasheet |
| STMicro LISY300AL | Gyro | 28-LGA | sparkfun | datasheet | |
| Analog Devices ADXL345 | Accelerometer | LGA | sparkfun | datasheet | |
| Linx Tech ANT-2.45-CHP-T | SMT Chip Antennae | Look at sheet for layout | N/A | digikey | datasheet |
| Toshiba TB6612FNG | Dual Motor Driver | 24-SSOP | digikey | datasheet | |
| Fairchild MMPQ3904 | Quad NPN | 200mA Ic, Low Vce Sat, for driving LEDs and whatnot | 16-SOIC | digikey | datasheet |
| China Young Sun LED Technology Co. YSL-R596CR3G4B5C-C10 | Tricolor RGB LED | N/A | sparkfun | datasheet | |
| Diode ZDT1053TA | Dual BJT NPN, 5A, 2.5W | Motor Current limiters, smaller than previous ones. Hopefully won't burn up from the power | SOT223-8 | digikey | datasheet |
| NXP PCA9306DP,118 | 2 Channel lever shifter | Supposed to be for I2C but also using it for all 3.3<->5V translations | 8-TSSOP | digikey | datasheet |
| Vishay SI3493BDV-T1-E3 | MOSFET, P-Channel, 20V, 8A | Reverse charger protection | 6-TSOP | digikey | datasheet |
| Diodes Inc. DMP2066LDM-7 | MOSFET, P-Channel, 20V, 4.6A | Reverse Battery protection, logic level | SOT26 | digikey | datasheet |
| Kingbright APT1608Q BC/D |
LED, Blue, 100mcd, 3.3V, 20mA | Power LEDs | 0603 | digikey | datasheet |
| Kingbright APG1608SURKC/T | LED, Red, 320mcd, 2V, 20mA | 0603 | digikey | datasheet | |
| Kingbright APG1608CGKC/T | LED, Green, 60mcd, 2.1V, 20mA | 0603 | digikey | datasheet | |
| SMT Button | SMT Button | N/A | sparkfun | datasheet | |
| Diodes DMMT3906W-7-F | PNP Transistor, Dual, 200mW | For orbs | SOT363 | digikey | datasheet |
| On Semiconductor NL27WZ14DFT2G | Dual Schmitt Trigger, Inverting | Button Debouncing, we were only using at most 4 of 6 of the hex inverters and this is smaller | SOT-363 | digikey | datasheet |
| Keystone 3000 | 12mm coin cell battery holder | for the rtc clock | N/A | newark | datasheet |
| Taiyo Yuden TMK107BJ104KA-T | 0.1uF ceramic cap, X5R | 0603 | digikey | datasheet | |
| TDK C1608X5R1C474K | 0.47uF cermaic cap, X5r | 0603 | digikey | datasheet | |
| TDK C1608X7R1E473K | 0.047uF ceramic cap, X7R | 0604 | digikey | datasheet | |
| AVX 0805YD106KAT2A | 10uF ceramic, x5R | 0805 | digikey | datasheet | |
| TDK C3216X5R0J156M | 15uF ceramic cap, x5R | 1206 | digikey | datasheet | |
| Murata GRM31CC80G476ME19L | 47uF ceramic cap, x6s | 1206 | digikey | datasheet | |
| Murata GRM188R71H102KA01D | 1000pF ceramic cap | 0603 | digikey | datasheet | |
| Murata GRM1885C1H202JA01D | 2000pF ceramic cap | 0603 | digikey | datasheet | |
| Kemet C0603C103K5RACTU | 0.01uF ceramic cap | 0603 | digikey | datasheet | |
| Murata GRM188R71A105KA61D | 1uF ceramic cap | 0603 | digikey | datasheet | |
| Vishay 293D104X9035A2TE3 | 0.1uF tantalum cap | 1206 | digikey | datasheet | |
| Kemet T499A224K035ATE18K | 0.22uF tantalum cap | 1206 | digikey | datasheet | |
| Kemet T491A106K010AT | 10uF tantalum cap | 1206 | digikey | datasheet | |
| Johanson Tech 251R14S180GV4T | 18pF, 2 % tolerance ceramic cap | 0603 | digikey | datasheet | |
| Yageo CC0603KRX7R6BB224 | 0.22uF ceramic cap | 0603 | digikey | datasheet | |
| Kemet C0805C475K9PACTU | 4.7uF ceramic cap | 0805 | digikey | datasheet | |
| Murata GRM1885C1H431JA01D | 430pF ceramic cap | 0603 | digikey | datasheet |
|
| Kemet C0603C100J5GACTU | 10pF, ceramic cap | 0603 | digikey | datasheet | |
| Taiyo Yuden HK16081N5S-T | 1.5nH inductor | Wireless amp antennae filter | 0603 | digikey | datasheet |
| TDK C1608C0G1H010B | 1pF ceramic cap | 0603 | digikey | datasheet | |
| ST Micro BAS69KFILM | Diode, 100mA | For RTC Battery | SOD523 | digikey | datasheet |
| Microchip MCP1702T-5002E/CB | 5V LDO, 250mA | For gas gauge power | SOT23 | digikey | datasheet |
| Panasonic ERJ-6BWFR010V | Resistor 0.01 Ohm, 1%, 1/4W | This is 5A max exactly, we should not exceed that, for the current sense resistor on the gas gauge | 0805 | digikey | datasheet |
| Assmann Electronics AU-Y1006-2-R | USB A Conenctor | SMT with 2 throughholes for mounting | N/A | digikey | datasheet |
| CTS 767143202G | Resnet, 2K, 7 Isolated | For Debug LEDs | 14-SOIC | digikey | datasheet |
| CTS 767141680G | Resnet, 68, 13 Bussed | For debug LEDs | 14-SOIC | digikey | datasheet |
| Stackpole CSRN 1 0.1 1% I | 0.1 Ohm, 1W Resistor | For MAX745 Sense resistor, charge current goes through it at 2A | 2010 | digikey | datasheet |
| Stackpole CSRN 2 0.5 1% I | 0.5 Ohm, 2W Rsistor | For the Motor driver current limiter | 2512 | digikey | datasheet |
| Comchip Technology CDSU101A | Diode, 80V, 100mA | For dropping the RTC voltage | 0603 | digikey | datasheet |
| CR1220 | 3.0V, CR1220 Coin Cell battery, lithium | RTC Backup/primary battery | CR1220 | allspecturm | N/A |
Removed Parts
| NCP584 | Logic Power Supply, 1.2V | 1.2V fixed LDO, 200mA max current. This handles the 1.2V domain. About a factor of 2.5 more current than we need? | SOT23-5 | digikey | datasheet |
| NXP Semiconductor BSS83,215 | MOSFET, N-Channel, 10V, 50mA | I2C Level Shifters | SOT143B | digikey | datasheet |
| Maxim DS2777G+ | Lithion Gas Gauge | Gas gauge and reverse battery protection. Note that min quantity is 34 and there is 17 day lead time | 14-TFDN | newark | datasheet |
| Epson Toyocom Corporation MC-405 32.7680K-A0 | Crystal, 32.768kHz | For the RTC | N/A | digikey | datasheet |
| ECS Inc. ECS-250-20-5G3XDS-F-TR | 25MHz Crystal | For the Ethernet PHY chip | N/A | digikey | datasheet |
| Micron MT46H32M16LFBF-5:B | DDR SDRAM, 512MB | listed in the datasheet for compatability | 60-VFBGA | digikey | datasheet |
| ON Semiconductor MJD31CG | NPN BJT Transistor, 3A, 100V | Motor current limiter | DPAK | digikey | datasheet |
| Bel Fuse Inc 0826-1L1T-57-F | 10/100 RJ45 Jack | Includes LEDs and Magnetics | N/A | digikey | datasheet |
| Lumex Opto SSA-LXB525SRD | 5 Seg LED Bar, Red | 1.7V, 30mA, For ARM debug | N/A | digikey | datasheet |
| Lumex Opto SSA-LXB525GD | 5 Seg, LED Bar, Green | 2.2V, 25mA, For ARM debug | N/A | digikey | datasheet |
| TI SN74AHC14DR | Hex Schmitt Trigger | Button debouncing | 15-SOIC | digikey | datasheet |
| Tyco 1981584-1 | USB Micro A/B Connector | Female end, SMT, might only be USB 1.0? It isn't that fake smt where there are throughole tabs which eagle can't seem to handle cleanly | N/A | digikey | datasheet |
| ECS ECS-250-20-30B-TR | 25MHz Crystal | For the Ethernet PHY, doesn't meet load capacitance numbers but none of the crystals seem to, this is smaller than the old one | N/A | digikey | datasheet |
| NXP LPC3240 | ARM9 Main Processor | FBGA | digikey | datasheet | |
| ST Micro NAND01GW3B2CZA6E | NAND Flash, 1GB | Cheap and its fits our requirements in terms of connectivity | 63-VFBGA | digikey | datasheet |
| On Semiconductor NSS30071MR6T1G | NPN Transistor, 30V, 700mA | For the LDO on the LT3507 | SC74-6 | digikey | datasheet |
| Panasonic EEF-CD1C4R7R | 4.7uF alelec cap | EIA-7343 | digikey | datasheet | |
| TDK C1608X5R1A225M | 2.2uF ceramic cap, x5r | 0603 | digikey | datasheet | |
| Kemet C0603C221K5RACTU | 220pF ceramic cap | 0603 | digikey | datasheet | |
| TDK C1608X7R1H152K | 1500pF ceramic cap | 0603 | digikey | datasheet | |
| TDK C1608X7R1H472K | 4700pF ceramic cap | 0603 | digikey | datasheet | |
| AVX 06031A330FAT2A | 33pF ceramic cap, 1% tolerance | 0603 | digikey | datasheet | |
| Murata GRM2165C1H392JA01D | 3900pF, 5% ceramic cap | 0603 | digikey | datasheet | |
| AVX 08052A151JAT2A | 150pF, 5% tolerance, ceramic cap | 0805 | digikey | datasheet | |
| ST Micro STOTG04EQTR | USB-OTG Phy | For the USB Controller. Handles OTG, device, and host | 24-QFN | digikey | datasheet |
| Atmel AT91SAM9260 | ARM9 | Has pretty much all of the NXP variety but in a qfp package | 208-qfp | digikey | datasheet |
| Atmel ATMEGA128 | Coprocessor | The standard and L variants are discontinued as of summer 2009, but no one carries the replacement yet. The new variant "A" runs at less power and is totally pin compatible | 64-QFN | digikey | datasheet |
| FTDI FT232R | USB<->Serial Converter | 32-QFN | digikey | datasheet | |
| Micron MT48H32M16LFBF-75:B TR | 512MB SDRAM, Mobile, 1.8V, 133MHz | There are issues using DDR on the ARM due to a bad CLKN pin, SDRAM is "safer", clocking it at 100MHz | 54-VFBGA | digikey | datasheet |
| Atmel AT45DB16 | 16Mbit Dataflash, SPI | Used to boot the ARM, only the AT45 family is supported, this is the only size in quantity | 8-SOIC | mouser | datasheet |
| 3M 2908-05WB-MG | Micro-SD Card Holder | SMT, Right angle, push/push micro sd card holder | N/A | digikey | datasheet-- |
| Atmel AT86RF231-ZU | Zigbee Chip | 32-QFN | digikey | datasheet | |
| TI CC2591RGVR | Antennae Amp | 16-QFN | digikey | datasheet | |
| Allegro Microsystems A4983SETTR-T | Stepper Motor Driver | 28-QFN | digikey | datasheet |