Difference between revisions of "Novena EVT to DVT changes"

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(→‎ECO13: Reduce attack surface by making DDC_SCL unidirectional)
(→‎ECO 31: Remove FPGA Done LED)
 
(18 intermediate revisions by the same user not shown)
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== ECO6: Gbit reflcock SI ==
 
== ECO6: Gbit reflcock SI ==
−
Drive strength of U10G is not strong enough to overcome series terminator. Replace with shunt.  
+
Drive strength of U10G is not strong enough to overcome series terminator. Replace with shunt. Add RC shunt terminator at the end of the transmission line instead.
 
{| class="wikitable sortable"
 
{| class="wikitable sortable"
 
|-
 
|-
Line 89: Line 89:
 
! scope="col" | Notes
 
! scope="col" | Notes
 
|-
 
|-
−
| R21G 49.9, 1% RESC1005N || R21G 0 ohm RESC1005N || '''Double-check routing, consider RC shunt terminator'''
+
| R21G 49.9, 1% RESC1005N || R21G 0 ohm RESC1005N ||  
 +
|-
 +
| none || R20S 49.9 1% ||
 +
|-
 +
| none || C16S 2200pF, X7R, 50V, 10% || cap needs tuning
 
|-
 
|-
 
|}
 
|}
Line 180: Line 184:
  
 
== ECO13: Reduce attack surface by making DDC_SCL unidirectional ==
 
== ECO13: Reduce attack surface by making DDC_SCL unidirectional ==
−
HDMI DDC and PMIC share the same I2C bus. This means that a hostile HDMI device could commandeer the I2C bus and attempt to reprogram the PMIC with values that can potentially cause permanent damage to the board. Prevent this by turning the DDC device into a slave only. This is accomplished by changing the level shifter on the bus into a unidirectional buffer. This prevents the trivial attack scenario on the board, where programmable I2C interface on an HDMI plug could be used to destroy a Novena (i.e., a simple software patch loaded into certain TV sets (particularly ones that grab updates via the internet) could accomplish this). Instead, a custom I2C-busting device (like an NeTV or bus pirate) must be made and physically connected to attack Novena using the remaining attack surface.
+
HDMI DDC and PMIC share the same I2C bus. This means that a hostile HDMI device could commandeer the I2C bus and attempt to reprogram the PMIC with values that can potentially cause permanent damage to the board. Prevent this by turning the DDC device into a slave only. This is accomplished by changing the level shifter on the bus into a unidirectional buffer. This prevents the trivial attack scenario on the board, where a programmable I2C interface on an HDMI plug could be used to destroy a Novena (i.e., a simple software patch loaded into certain TV sets (particularly ones that grab updates via the internet) could accomplish this). Instead, a custom I2C-busting device (like an NeTV or bus pirate) must be made and physically connected to attack Novena using the remaining attack surface.
  
−
The remaining attack surface consists of monitoring the SCL/SDA lines and attempting to modify the I2C bus on-the-fly by overriding the SDA line's value using a very strong driver. This can be accomplished by simply waiting for any transaction on the bus where SCL is toggled, and modifying both the destination address and data packets (this is done by an NeTV, for example). One work around is to disable all traffic to the PMIC's I2C bus as long as an HDMI device is plugged in. This is not a totally unreasonable scenario, as it basically means the device is locked in the "on" state if it's driving an external projector.  
+
The remaining attack surface consists of monitoring the SCL/SDA lines and attempting to modify the I2C bus on-the-fly by overriding the SDA line's value using a very strong driver. This can be accomplished by simply waiting for any transaction on the bus where SCL is toggled, and modifying both the destination address and data packets (this is done by an NeTV, for example). One countermeasure is to disable all traffic to the PMIC's I2C bus as long as an HDMI device is plugged in. This is not a totally unreasonable scenario, as it basically means the device is locked in the "on" state if it's driving an external projector.  
  
−
Of course, the actual chance of this attack being executed is small to none.  
+
Of course, if someone had it about them to break into your office and mod the I2C lines in your HDMI interface to your external monitor, they probably could just as easily smash your laptop, mod your AC adapter, or mess with your USB cables and cause you similar trouble. So I think this remaining attack surface is comparable to other existing attack surfaces, and therefore not a high priority to button up.
  
 
{| class="wikitable sortable"
 
{| class="wikitable sortable"
Line 245: Line 249:
 
== ECO17: Refactor LCD connector==
 
== ECO17: Refactor LCD connector==
 
Instead of relying on a discrete-wire cable, flex circuit headers will be used to connect to the LCD. These are cheaper and easier to make in small quantities than the discrete-wire cables. This enables a multiplicity of displays to be adapted to the board with a lower overhead cost.  
 
Instead of relying on a discrete-wire cable, flex circuit headers will be used to connect to the LCD. These are cheaper and easier to make in small quantities than the discrete-wire cables. This enables a multiplicity of displays to be adapted to the board with a lower overhead cost.  
 +
 +
* Wire up LVDS0_TX3_[N,P] and LVDS1_TX3_[N,P] to support 8-bit color depths on all channels (better banding performance on IPS displays)
 +
* Remove resistive touch screen headers and merge signals into FFC breakout
 +
* Due to high signal speeds, minimize FFC length, and use local adapter/repeater board for super high resolution displays
 +
 +
{| class="wikitable sortable"
 +
|-
 +
! scope="col" | EVT
 +
! scope="col" | DVT
 +
! scope="col" | Notes
 +
|-
 +
| JP10L HRS FX15S-41S-0.5SH || Molex 51296-5494 or equiv ||
 +
|-
 +
| P14D AMP 487951-4 || removed || merged into JP10L
 +
|-
 +
| P15D Male 2.5mm 4x1 right-angle header (DNP) || removed ||
 +
|-
 +
|
 +
|}
 +
 +
== ECO18: Move status LED ==
 +
Status LED needs to be moved to edge of board and made right-angle for compatibility with router-case ID
 +
 +
{| class="wikitable sortable"
 +
|-
 +
! scope="col" | EVT
 +
! scope="col" | DVT
 +
! scope="col" | Notes
 +
|-
 +
| D14D APT1608SGC || D14D LTST-270KGKT || same color (green), changed to right angle
 +
|-
 +
|}
 +
 +
== ECO19: Refactor blinkenlight header ==
 +
A small header is provided for general-purpose switches and blinkenlight for miscellaneous case integration needs. Currently, there is no solid requirement driving the needs of the header. However, the header is occupying a very valuable routing channel.
 +
 +
Change header from through-hole to surface-mount, and reduce pin count to something more likely needed (6 total I/Os)
 +
 +
* Remove key_row4/key_col4 pins
 +
* ECSPI3_RDY signal removed (not needed due to no Rpi header)
 +
* P16D TS_ANA wired up to header (just so we have one "housekeeping" analog input available, e.g. for light sensor or temp sensor)
 +
{| class="wikitable sortable"
 +
|-
 +
! scope="col" | EVT
 +
! scope="col" | DVT
 +
! scope="col" | Notes
 +
|-
 +
| P16D Male 8x2 2.54mm || P16D HRS F19SC-8S-0.5SH ||
 +
|-
 +
|}
 +
 +
== ECO20: Make LCD off-state bleed stronger ==
 +
Experience with the audio codec indicates existing 330 ohm resistor is probably too weak to fight substantial leakage.
 +
 +
{| class="wikitable sortable"
 +
|-
 +
! scope="col" | EVT
 +
! scope="col" | DVT
 +
! scope="col" | Notes
 +
|-
 +
| R17L 330, 1% || 49.9, 1%
 +
|-
 +
|}
 +
 +
== ECO21: Upgrade FPGA and power supply ==
 +
Upgrade FPGA from Spartan 6 LX9 to LX45 -- enable more application such as digital oscope, logic analyzer, SDR, etc.
 +
 +
Upgrade capability of FPGA 1.2V VCCINT supply from 1A to 2A -- in anticipation of larger, more complex FPGA designs.
 +
 +
{| class="wikitable sortable"
 +
|-
 +
! scope="col" | EVT
 +
! scope="col" | DVT
 +
! scope="col" | Notes
 +
|-
 +
| U800 XC6SLX9-2CSG324C  || U800 XC6SLX45-3CSG324C || supports 800MT/s DDR3, larger capacity for more fun!
 +
|-
 +
| U10F LMR10510YSD || U10F LMR10520YSDE
 +
|-
 +
| L10F 2.2uF, coilcraft MSS5121-22ML || 2.2uH, coilcraft MSS5131-222ML || same 2.3A max current, slight upgrade in Irms
 +
|-
 +
| D11F CDBM140-G || D11F CDBMT220L-G || same footprint
 +
|-
 +
| R19F 10k, 1% || R19F 10.5k, 1% || increase Vccint of FPGA to allow for 800MT/s DDR3
 +
|-
 +
| C65F 4.7uF, 10V, X5R, 10% || C65F 10uF, 10V, X5R, 20% || both CAPC1608N
 +
|-
 +
| C62F, C63F 10uF, 10V, X5R, 20% CAP1608N || C62F, C63F 22uF, 6.3V, X5R, 20% CAPC1608N_HD ||
 +
|-
 +
|}
 +
 +
== ECO22: Remove low-speed FPGA ADC ==
 +
Making room for the hyperspace bypass. Actually, just a dual, 8-bit 800MSPS ADC. Or a single 12-bit 800MSPS ADC. Or another low-speed ADC, if you care.
 +
 +
{| class="wikitable sortable"
 +
|-
 +
! scope="col" | EVT
 +
! scope="col" | DVT
 +
! scope="col" | Notes
 +
|-
 +
| R28F 10k, 1% || removed ||
 +
|-
 +
| C68F 4.7uF, 10V, X5R, 10% || removed ||
 +
|-
 +
| C69F 0.1uF, 25V, X5R || removed ||
 +
|-
 +
| U12F ADC108S022  || removed ||
 +
|-
 +
| C67F 0.1uF, 6.3V, X5R  || removed ||
 +
|-
 +
| U15F LP2980IM5-3.3 || removed ||
 +
|-
 +
| C70F 4.7uF, 10V X5R, 10%  || removed ||
 +
|-
 +
| C71F 0.1uF, 25V X5R || removed ||
 +
|-
 +
| D13F, D16F  RCLAMP0524P || removed ||
 +
|-
 +
| RP10F, RP13F 220/RP || removed ||
 +
|-
 +
| P11F Female 8x1 2.54mm header || removed ||
 +
|-
 +
| P12F Female 8x2 2.54mm header || removed ||
 +
|-
 +
| D18F ESD5Z2.5T1 || removed ||
 +
|-
 +
| C72F 1.0uF, 25V, 20% X5R || removed ||
 +
|-
 +
| R28A 0 ohm (DNP) || removed || no longer relevant since VANA removed in this ECO
 +
|-
 +
|}
 +
 +
== ECO23: Remove low-speed digital I/O ==
 +
Removed in favor of routing a dozen high-speed capable digital I/O to a high-speed header.
 +
 +
{| class="wikitable sortable"
 +
|-
 +
! scope="col" | EVT
 +
! scope="col" | DVT
 +
! scope="col" | Notes
 +
|-
 +
| D17F, D14F RCLAMP0524P || removed ||
 +
|-
 +
| RP11F, RP14F 22/RP || removed ||
 +
|-
 +
| P13F Female 8x1 2.54mm header || removed ||
 +
|-
 +
| P14F Female 8x2 2.54mm header || removed ||
 +
|-
 +
| D20F ESD5Z2.5T1 || removed ||
 +
|-
 +
| C73F 1.0uF, 25V, 20% X5R || removed ||
 +
|-
 +
|}
 +
 +
== ECO24: Remove PWM I/O ==
 +
Removed in favor of routing a dozen high-speed capable digital I/O to a high-speed header.
 +
 +
{| class="wikitable sortable"
 +
|-
 +
! scope="col" | EVT
 +
! scope="col" | DVT
 +
! scope="col" | Notes
 +
|-
 +
| D19F, D15F RCLAMP0524P || removed ||
 +
|-
 +
| RP12F, RP15F 220/RP || removed ||
 +
|-
 +
| P15F Female 8x2 2.54mm header || removed ||
 +
|-
 +
| P16F Female 8x1 2.54mm header || removed ||
 +
|-
 +
| P_PWM 2 pin 1.27mm male header || removed ||
 +
|-
 +
| D21F RSA5M || removed ||
 +
|-
 +
| C74F 1.0uF, 25V, 20% X5R || removed ||
 +
|-
 +
|}
 +
 +
== ECO25: Remove I2C FPGA ROM ==
 +
The I2C FPGA ROM is deemed redundant with the SPI option. The SPI option allows for a higher capacity part that costs about the same. Also, there is no clear requirement for this part, it's simply available "just in case".
 +
 +
{| class="wikitable sortable"
 +
|-
 +
! scope="col" | EVT
 +
! scope="col" | DVT
 +
! scope="col" | Notes
 +
|-
 +
| U13F 24LC32A-I/ST || removed ||
 +
|-
 +
| R29F, R30F 2.2k, 1% || removed ||
 +
|-
 +
| P_LI2C_WP 2 pin 1.27mm male header || removed ||
 +
|-
 +
|}
 +
 +
== ECO26: Add DDR3 memory to FPGA ==
 +
Adding a local DDR3 memory device to the FPGA. Trying for a 16-bit part so total B/W capable is 1.6 GB/s, sufficient for buffering high-speed ADC capture traces, etc.
 +
 +
Some signals are moved to a new bank:
 +
* AUD_MCLK displaced
 +
* EPIT_EPIT0 displaced
 +
* CLK2_P/_N displaced to bank 2
 +
* UIM_PWR displaced
 +
* FPGA_LED2 displaced
 +
* DDC_SCL, DDC_SDA displaced
 +
* RESETB_MCU displaced
 +
 +
In addition, C15F-C21F capacitors changed from 3.3V to 1.5V rails, as bank 1 is now a 1.5V VCCIO bank.
  
 
{| class="wikitable sortable"
 
{| class="wikitable sortable"
Line 252: Line 466:
 
! scope="col" | Notes
 
! scope="col" | Notes
 
|-
 
|-
−
| JP10L HRS FX15S-41S-0.5SH || TBD ||
+
| (none) || U12F MT41J128M16HA-125 || 128M x 16 bit wide DDR3 -- 2 Gbits total
 +
|-
 +
| (none) || R28F 100, 1% ||
 +
|-
 +
| (none) || R31F 100, 1% (DNP) || just in case a clock tuning is needed
 +
|-
 +
| (none) || R32F 4.7k, 1% ||
 +
|-
 +
| (none) || R34F 240, 1% added ||
 +
|-
 +
| (none) || R33F 4.7k, 1% added ||
 +
|-
 +
| (none) || C72F-C80F and C84F-C91F 0.1uF, 6.3V X5R 0201 || note multiple P/Ns
 +
|-
 +
| (none) || C70F 1.0uF, 25V 20% X5R added ||
 +
|-
 +
| (none) || C71F, C67F 10uF, 10V X5R 20% added ||
 +
|-
 +
| (none) || C68F, C69F 0.1uF, 6.3V X5R 0201 added ||
 +
|-
 +
|}
 +
 
 +
== ECO27: Add high-speed expansion header to FPGA ==
 +
Add header capable of high-speed differential (Gbit-speeds) expansion to the FPGA.
 +
 
 +
Power is provisioned at 1.5A @ 5V. Intention is for expansion card to have local power converters from the 5V line.
 +
 
 +
Pin-out has:
 +
 
 +
* 16 high-speed LVDS-capable data lines
 +
* 2 high-speed LVDS clock lines
 +
* 2 high-speed LVDS status lines (e.g. for overflow signal)
 +
* approx 16-20 digital lines, intended for single-ended use. These are for configuring the high speed ADC, input voltage range, and also to serve as inputs for logic analysis purposes.
 +
* All I/Os can be configured, inside the FPGA, as low-speed 3.3V-capable digital I/O.
 +
 
 +
The goal is to support up to two channels 8-bit 800MSPS+ data capture, plus 8+ lines of logic analysis (ideally 16, but depends on routability). Since it's an add-on card, this could also be configured as a single 12-bit 800MSPS+ data capture with more digital I/O.
 +
 
 +
{| class="wikitable sortable"
 +
|-
 +
! scope="col" | EVT
 +
! scope="col" | DVT
 +
! scope="col" | Notes
 +
|-
 +
| (none) || JP10F FX10A-80S/SV(**) || Receptacle on mainboard, so 4mm or 5mm header can be put on the daughtercard. Rated to 10 GHz.
 +
|-
 +
| (none) || C82F 10uF, 10V, X5R, 20% ||
 +
|-
 +
| (none) || C83F 0.1uF, 25V, X5R ||
 +
|-
 +
|}
 +
 
 +
== ECO 28: Remove CCLK terms ==
 +
CCLK is greatly shortened due to removal of Rpi header. Trace length is now just 750 mils. Termination is no longer needed.
 +
 
 +
 
 +
{| class="wikitable sortable"
 +
|-
 +
! scope="col" | EVT
 +
! scope="col" | DVT
 +
! scope="col" | Notes
 +
|-
 +
| R10F, R11F 100, 1% || removed ||
 +
|-
 +
|}
 +
 
 +
== ECO 29: Add DDR3 VREF options ==
 +
Add option to generate DDR3 VREF locally, improve bypassing of the lines.
 +
 
 +
{| class="wikitable sortable"
 +
|-
 +
! scope="col" | EVT
 +
! scope="col" | DVT
 +
! scope="col" | Notes
 +
|-
 +
| (none) || C92F, C93F 0.1uF, 6.3V, X5R ||
 +
|-
 +
| (none) || C94F 1.0uF, 25V, 20%, X5R ||
 +
|-
 +
| (none) || R10F 0ohm, 0805 || depopulate for local VREF
 +
|-
 +
| (none) || R11F, R29F  1k, 1% (DNP) || populate for local VREF
 +
|-
 +
|}
 +
 
 +
== ECO 30: SATA power cap interferes with expansion port ==
 +
The 220uF bulk decap on SATA switched power port is too tall; it prevents a daughtercard from mounting for the FPGA expansion.
 +
 
 +
Replace with a pair of 22uF caps. This decision was made because (a) I don't like tantalums (b) getting another unique low-profile aluminum cap into inventory would be expensive and (c) as long as we're using SSDs I think we should be fine with 50uF total capacitance on the line. The big cap is questionably necessary, and if so, probably only for spinning disks.
 +
 
 +
{| class="wikitable sortable"
 +
|-
 +
! scope="col" | EVT
 +
! scope="col" | DVT
 +
! scope="col" | Notes
 +
|-
 +
| (none) || C22H 22uF,10V, X5R, 20% ||
 +
|-
 +
| C11H 220uF, 10V, VS D || C11H 22uF, 10V, X5R, 20% ||
 +
|-
 +
|}
 +
 
 +
== ECO 31: Remove FPGA Done LED ==
 +
Ain't nobody got time fo' that.
 +
 
 +
Seriously, though, they don't. It's not even populated and it's in the way.
 +
{| class="wikitable sortable"
 +
|-
 +
! scope="col" | EVT
 +
! scope="col" | DVT
 +
! scope="col" | Notes
 +
|-
 +
| Kingbright APT1608SGC green (DNP) || removed ||
 +
|-
 +
| R22F 330, 1% || R22F 4.7k, 1% ||
 +
|-
 +
|}
 +
 
 +
== ECO 32: Add power switch to FPGA expansion card ==
 +
In standby/hibernate modes, we probably want to be able to turn off the power-hungry analog front ends on the expansion slot. Add a power switch that defaults to 'on', but wired to CPU to give an option to power down the expansion card.
 +
 
 +
'''software change required''': Power enable is wired to SD1_DAT1 / ball C20.
 +
 
 +
{| class="wikitable sortable"
 +
|-
 +
! scope="col" | EVT
 +
! scope="col" | DVT
 +
! scope="col" | Notes
 +
|-
 +
| (none) || Q11F Si4435DY ||
 +
|-
 +
| (none) || Q12F 2N7002W ||
 +
|-
 +
| (none) || R35F 10k, 1% ||
 +
|-
 +
| (none) || R36F 10k, 1% ||
 +
|-
 +
| (none) || R30F 100k, 1% ||
 +
|-
 +
| (none) || C95F 1.0uF, 25V, 20% X5R ||
 
|-
 
|-
 
|}
 
|}

Latest revision as of 16:30, 27 March 2013

Novena EVT to DVT changes

This is a list of all the changes applied to the board from EVT1A to DVT1 release. If it's not on this list, it didn't happen.

Each change has the format of issue summary/resolution, and specific change

ECO1: Inrush current limit

The RC constant governing the turn-on/turn-off rates of the FET power switches needs tuning. In EVT, most switches are turning on too quickly for them to be effective. Resolution is to increase capacitance and resistance.

EVT DVT Notes
R38N 330, 1% / REC1005N R38N 10k, 1% / RESC1005N P3.3V_DELAYED
C30N 0.1uF, 6.3V, X5R / CAPC0603N_B C30N 1.0uF, 25V, 20% X5R / CAPC1608N P3.3V_DELAYED
R29N 330, 1% / REC1005N R29N 10k, 1% / RESC1005N P5.0V_DELAYED
C27N 0.1uF, 6.3V, X5R / CAPC0603N_B C27N 1.0uF, 25V, 20% X5R / CAPC1608N P5.0V_DELAYED
R11H 330, 1% / REC1005N R11H 10k, 1% / RESC1005N SATA_PWRON
C10H 0.1uF, 6.3V, X5R / CAPC0603N_B C10H 1.0uF, 25V, 20% X5R / CAPC1608N SATA_PWRON
C10X 0.1uF, 6.3V, X5R / CAPC0603N_B C10X 1.0uF, 25V, 20% X5R / CAPC1608N PCIE_PWRON
R15L 1k, 1% / REC1005N R15L 10k, 1% / RESC1005N LCD_VCC_SW
C14L 0.1uF, 6.3V, X5R / CAPC0603N_B C14L 1.0uF, 25V, 20% X5R / CAPC1608N LCD_VCC_SW
C19L 0.1uF, 25V, X5R / CAPC1005N C19L 1.0uF, 25V, 20% X5R / CAPC1608N LCD_BL_VDD

ECO2: FPGA boot fuse interference

FPGA's internal pull-ups on boot will yank boot fuses to the CPU, causing wrong boot source to be selected.

EVT DVT Notes
R12F 4.7k, 1% / REC1005N R12F 4.7k, 1% (DNP) / RESC1005N depop pull-down
R13F 4.7k, 1% (DNP) / REC1005N R13F 4.7k, 1% / RESC1005N populate pull-up

ECO3: Gbit Ethernet Reset

Default circuit recommended by reference design is bogus. Get rid of it.

EVT DVT Notes
C32G 10uF, 10V, X5R, 20% removed
D11G BAT54T1G removed
D12G BAT54T1G removed
R20G 10k, 1% R20G 10k, 1% (DNP) also changed to pull to ground by default

ECO4: PCIe power on

Wire PCI express power on line (gate of Q10X) to ball R1 / pad name GPIO_17 / "GPIO7[12] aka 6 * 32 + 12 = GPIO 204". Software change required

ECO5: Improve magnetics termination

The magnetics in the PHY are not terminated properly, causing ISSI.

EVT DVT Notes
R14G 0 ohm R14G 0 ohm (DNP) also move EN1G_3.3VA line to other side of decaps on CT

ECO6: Gbit reflcock SI

Drive strength of U10G is not strong enough to overcome series terminator. Replace with shunt. Add RC shunt terminator at the end of the transmission line instead.

EVT DVT Notes
R21G 49.9, 1% RESC1005N R21G 0 ohm RESC1005N
none R20S 49.9 1%
none C16S 2200pF, X7R, 50V, 10% cap needs tuning

ECO7: HDMI HPD polarity

HDMI HPD polarity is not software programmable, so need to buffer (not invert) incoming signal.

EVT DVT Notes
R28L 0 ohm R28L 0 ohm (DNP)
R27L 0 ohm (DNP) R27L 0 ohm
Q17L 2N7002W (DNP) Q17L 2N7002W
R29L 10k, 1% (DNP) R29L 10k, 1%

ECO8: Audio chip sucks (power)

During power down, audio chip totally leaks power through the I2C bus. Need to really strengthen the pull-down to fully reset the chip and fight the pull-ups on I2C.

EVT DVT Notes
R21A 100, 1% R21A 20 ohms, 1%,0402 10 ohm on EVT1A, but should be effective at 20 ohms. 10 ohms would be a new component, if lower value is needed go to 8.06 1% (from R10N)

ECO9: Reset pulse too short

The PFUZE PMIC reset cycle is too short, approx 2 ms after VGEN6 (last supply) rises. Since there are other supplies slaved off of VGEN5/6 enables stabilizing, reset pulse needs to be lengthened. Use a standard reset monitor on the +5V line, which ensures a minimum 100ms total reset pulse width from 5V stable; provides plenty of margin for system to stabilize (~50ms or so).

EVT DVT Notes
(none) U14N APX803-44-SAG-7 or RT9818CXXGVL 4.2V-4.38V setpoint multiple parts can serve this role
(none) C33N 0.1uF, 25V, X5R

ECO10: Input cap bleed

If there is an error condition on U11N, the chip goes into shut down. The leakage in protect mode is sufficiently small that it takes several seconds for the input caps to bleed down to a point where the error condition is cleared. This can lead to a bad user experience. For fixed installations, a 2.2k resistor is installed to bleed current on the input. This wastes about 65mW of power, but the capacitors now discharge in under a second. For battery/mobile installations, the resistor should *not* be installed, and instead the battery board should either guarantee sufficient time for a power cycle or there should be a switched pull-down on the battery board side to clear the error condition.

EVT DVT Notes
(none) R31N 2.2k, 1%

ECO11: Split audio record/playback clocks

The audio codec requires independent clocks for record and playback (in part to allow for dissimilar sample rates during full duplex operation).

  • ALRCK is connected to what is currently LCD_BL_ON
  • LCD_BL_ON is connected to what is currently KEY_ROW4
  • User switch is no longer bridging GPIOs, it's now a button shorting a pull-up to ground
EVT DVT Notes
(none) R15S 10k, 1% software change required -- key col4 is normally pulled up, and goes low when user switch is hit
(none) C15S 0.1uF, 6.3V, X5R

ECO12: Add user switch on bottom side

Add a user switch (mirror image) on bottom side of PCB to be compatible with new ID

EVT DVT Notes
(none) SW11S TS-1187A, Chi Fung

ECO13: Reduce attack surface by making DDC_SCL unidirectional

HDMI DDC and PMIC share the same I2C bus. This means that a hostile HDMI device could commandeer the I2C bus and attempt to reprogram the PMIC with values that can potentially cause permanent damage to the board. Prevent this by turning the DDC device into a slave only. This is accomplished by changing the level shifter on the bus into a unidirectional buffer. This prevents the trivial attack scenario on the board, where a programmable I2C interface on an HDMI plug could be used to destroy a Novena (i.e., a simple software patch loaded into certain TV sets (particularly ones that grab updates via the internet) could accomplish this). Instead, a custom I2C-busting device (like an NeTV or bus pirate) must be made and physically connected to attack Novena using the remaining attack surface.

The remaining attack surface consists of monitoring the SCL/SDA lines and attempting to modify the I2C bus on-the-fly by overriding the SDA line's value using a very strong driver. This can be accomplished by simply waiting for any transaction on the bus where SCL is toggled, and modifying both the destination address and data packets (this is done by an NeTV, for example). One countermeasure is to disable all traffic to the PMIC's I2C bus as long as an HDMI device is plugged in. This is not a totally unreasonable scenario, as it basically means the device is locked in the "on" state if it's driving an external projector.

Of course, if someone had it about them to break into your office and mod the I2C lines in your HDMI interface to your external monitor, they probably could just as easily smash your laptop, mod your AC adapter, or mess with your USB cables and cause you similar trouble. So I think this remaining attack surface is comparable to other existing attack surfaces, and therefore not a high priority to button up.

EVT DVT Notes
(none) R33L 47k, 1% set to a high value to prevent leakage, but should still be fast enough for I2C use
(none) Q19L BSS138

ECO 14: Fix L11N footprint

Footprint for L11N was mistakenly set to MSS1048; should be sized for XAL4020.

EVT DVT Notes
L11N Wurth 7447797050 0.50uH 8.5A / COILCRAFT_MSS1048 L11N Coilcraft 0.60uH 10.4A XAL4020-601ME / COILCRAFT_XAL4020

ECO 15: Drop silicon mic feature

Silicon mic built-into motherboard is being dropped. If a microphone is required, one must plug in an android or iphone compatible hands-free headset that contains a mic. The silicon mic is dropped in part due to privacy concerns.

Note that connector to support an add-on board for an external silicon mic is still provisioned.

EVT DVT Notes
U13A MP34DT01 U13A MP34DT01 (DNP)

ECO 16: Drop Raspberry Pi header

No value is seen in keeping the Rpi header; it takes a lot of space, has an inferior pin-out, and probably nobody will actually use it. The board space will instead be allocated to a new header that more intelligently uses the high-speed differential pairs available on the FPGA for expansion and prototyping.

EVT DVT Notes
P13D Male 13x2 2.54mm header (none)
C13D 0.1uF, 25V, X5R (none)
C12D 0.1uF, 25V, X5R (none)

ECO17: Refactor LCD connector

Instead of relying on a discrete-wire cable, flex circuit headers will be used to connect to the LCD. These are cheaper and easier to make in small quantities than the discrete-wire cables. This enables a multiplicity of displays to be adapted to the board with a lower overhead cost.

  • Wire up LVDS0_TX3_[N,P] and LVDS1_TX3_[N,P] to support 8-bit color depths on all channels (better banding performance on IPS displays)
  • Remove resistive touch screen headers and merge signals into FFC breakout
  • Due to high signal speeds, minimize FFC length, and use local adapter/repeater board for super high resolution displays
EVT DVT Notes
JP10L HRS FX15S-41S-0.5SH Molex 51296-5494 or equiv
P14D AMP 487951-4 removed merged into JP10L
P15D Male 2.5mm 4x1 right-angle header (DNP) removed

ECO18: Move status LED

Status LED needs to be moved to edge of board and made right-angle for compatibility with router-case ID

EVT DVT Notes
D14D APT1608SGC D14D LTST-270KGKT same color (green), changed to right angle

ECO19: Refactor blinkenlight header

A small header is provided for general-purpose switches and blinkenlight for miscellaneous case integration needs. Currently, there is no solid requirement driving the needs of the header. However, the header is occupying a very valuable routing channel.

Change header from through-hole to surface-mount, and reduce pin count to something more likely needed (6 total I/Os)

  • Remove key_row4/key_col4 pins
  • ECSPI3_RDY signal removed (not needed due to no Rpi header)
  • P16D TS_ANA wired up to header (just so we have one "housekeeping" analog input available, e.g. for light sensor or temp sensor)
EVT DVT Notes
P16D Male 8x2 2.54mm P16D HRS F19SC-8S-0.5SH

ECO20: Make LCD off-state bleed stronger

Experience with the audio codec indicates existing 330 ohm resistor is probably too weak to fight substantial leakage.

EVT DVT Notes
R17L 330, 1% 49.9, 1%

ECO21: Upgrade FPGA and power supply

Upgrade FPGA from Spartan 6 LX9 to LX45 -- enable more application such as digital oscope, logic analyzer, SDR, etc.

Upgrade capability of FPGA 1.2V VCCINT supply from 1A to 2A -- in anticipation of larger, more complex FPGA designs.

EVT DVT Notes
U800 XC6SLX9-2CSG324C U800 XC6SLX45-3CSG324C supports 800MT/s DDR3, larger capacity for more fun!
U10F LMR10510YSD U10F LMR10520YSDE
L10F 2.2uF, coilcraft MSS5121-22ML 2.2uH, coilcraft MSS5131-222ML same 2.3A max current, slight upgrade in Irms
D11F CDBM140-G D11F CDBMT220L-G same footprint
R19F 10k, 1% R19F 10.5k, 1% increase Vccint of FPGA to allow for 800MT/s DDR3
C65F 4.7uF, 10V, X5R, 10% C65F 10uF, 10V, X5R, 20% both CAPC1608N
C62F, C63F 10uF, 10V, X5R, 20% CAP1608N C62F, C63F 22uF, 6.3V, X5R, 20% CAPC1608N_HD

ECO22: Remove low-speed FPGA ADC

Making room for the hyperspace bypass. Actually, just a dual, 8-bit 800MSPS ADC. Or a single 12-bit 800MSPS ADC. Or another low-speed ADC, if you care.

EVT DVT Notes
R28F 10k, 1% removed
C68F 4.7uF, 10V, X5R, 10% removed
C69F 0.1uF, 25V, X5R removed
U12F ADC108S022 removed
C67F 0.1uF, 6.3V, X5R removed
U15F LP2980IM5-3.3 removed
C70F 4.7uF, 10V X5R, 10% removed
C71F 0.1uF, 25V X5R removed
D13F, D16F RCLAMP0524P removed
RP10F, RP13F 220/RP removed
P11F Female 8x1 2.54mm header removed
P12F Female 8x2 2.54mm header removed
D18F ESD5Z2.5T1 removed
C72F 1.0uF, 25V, 20% X5R removed
R28A 0 ohm (DNP) removed no longer relevant since VANA removed in this ECO

ECO23: Remove low-speed digital I/O

Removed in favor of routing a dozen high-speed capable digital I/O to a high-speed header.

EVT DVT Notes
D17F, D14F RCLAMP0524P removed
RP11F, RP14F 22/RP removed
P13F Female 8x1 2.54mm header removed
P14F Female 8x2 2.54mm header removed
D20F ESD5Z2.5T1 removed
C73F 1.0uF, 25V, 20% X5R removed

ECO24: Remove PWM I/O

Removed in favor of routing a dozen high-speed capable digital I/O to a high-speed header.

EVT DVT Notes
D19F, D15F RCLAMP0524P removed
RP12F, RP15F 220/RP removed
P15F Female 8x2 2.54mm header removed
P16F Female 8x1 2.54mm header removed
P_PWM 2 pin 1.27mm male header removed
D21F RSA5M removed
C74F 1.0uF, 25V, 20% X5R removed

ECO25: Remove I2C FPGA ROM

The I2C FPGA ROM is deemed redundant with the SPI option. The SPI option allows for a higher capacity part that costs about the same. Also, there is no clear requirement for this part, it's simply available "just in case".

EVT DVT Notes
U13F 24LC32A-I/ST removed
R29F, R30F 2.2k, 1% removed
P_LI2C_WP 2 pin 1.27mm male header removed

ECO26: Add DDR3 memory to FPGA

Adding a local DDR3 memory device to the FPGA. Trying for a 16-bit part so total B/W capable is 1.6 GB/s, sufficient for buffering high-speed ADC capture traces, etc.

Some signals are moved to a new bank:

  • AUD_MCLK displaced
  • EPIT_EPIT0 displaced
  • CLK2_P/_N displaced to bank 2
  • UIM_PWR displaced
  • FPGA_LED2 displaced
  • DDC_SCL, DDC_SDA displaced
  • RESETB_MCU displaced

In addition, C15F-C21F capacitors changed from 3.3V to 1.5V rails, as bank 1 is now a 1.5V VCCIO bank.

EVT DVT Notes
(none) U12F MT41J128M16HA-125 128M x 16 bit wide DDR3 -- 2 Gbits total
(none) R28F 100, 1%
(none) R31F 100, 1% (DNP) just in case a clock tuning is needed
(none) R32F 4.7k, 1%
(none) R34F 240, 1% added
(none) R33F 4.7k, 1% added
(none) C72F-C80F and C84F-C91F 0.1uF, 6.3V X5R 0201 note multiple P/Ns
(none) C70F 1.0uF, 25V 20% X5R added
(none) C71F, C67F 10uF, 10V X5R 20% added
(none) C68F, C69F 0.1uF, 6.3V X5R 0201 added

ECO27: Add high-speed expansion header to FPGA

Add header capable of high-speed differential (Gbit-speeds) expansion to the FPGA.

Power is provisioned at 1.5A @ 5V. Intention is for expansion card to have local power converters from the 5V line.

Pin-out has:

  • 16 high-speed LVDS-capable data lines
  • 2 high-speed LVDS clock lines
  • 2 high-speed LVDS status lines (e.g. for overflow signal)
  • approx 16-20 digital lines, intended for single-ended use. These are for configuring the high speed ADC, input voltage range, and also to serve as inputs for logic analysis purposes.
  • All I/Os can be configured, inside the FPGA, as low-speed 3.3V-capable digital I/O.

The goal is to support up to two channels 8-bit 800MSPS+ data capture, plus 8+ lines of logic analysis (ideally 16, but depends on routability). Since it's an add-on card, this could also be configured as a single 12-bit 800MSPS+ data capture with more digital I/O.

EVT DVT Notes
(none) JP10F FX10A-80S/SV(**) Receptacle on mainboard, so 4mm or 5mm header can be put on the daughtercard. Rated to 10 GHz.
(none) C82F 10uF, 10V, X5R, 20%
(none) C83F 0.1uF, 25V, X5R

ECO 28: Remove CCLK terms

CCLK is greatly shortened due to removal of Rpi header. Trace length is now just 750 mils. Termination is no longer needed.


EVT DVT Notes
R10F, R11F 100, 1% removed

ECO 29: Add DDR3 VREF options

Add option to generate DDR3 VREF locally, improve bypassing of the lines.

EVT DVT Notes
(none) C92F, C93F 0.1uF, 6.3V, X5R
(none) C94F 1.0uF, 25V, 20%, X5R
(none) R10F 0ohm, 0805 depopulate for local VREF
(none) R11F, R29F 1k, 1% (DNP) populate for local VREF

ECO 30: SATA power cap interferes with expansion port

The 220uF bulk decap on SATA switched power port is too tall; it prevents a daughtercard from mounting for the FPGA expansion.

Replace with a pair of 22uF caps. This decision was made because (a) I don't like tantalums (b) getting another unique low-profile aluminum cap into inventory would be expensive and (c) as long as we're using SSDs I think we should be fine with 50uF total capacitance on the line. The big cap is questionably necessary, and if so, probably only for spinning disks.

EVT DVT Notes
(none) C22H 22uF,10V, X5R, 20%
C11H 220uF, 10V, VS D C11H 22uF, 10V, X5R, 20%

ECO 31: Remove FPGA Done LED

Ain't nobody got time fo' that.

Seriously, though, they don't. It's not even populated and it's in the way.

EVT DVT Notes
Kingbright APT1608SGC green (DNP) removed
R22F 330, 1% R22F 4.7k, 1%

ECO 32: Add power switch to FPGA expansion card

In standby/hibernate modes, we probably want to be able to turn off the power-hungry analog front ends on the expansion slot. Add a power switch that defaults to 'on', but wired to CPU to give an option to power down the expansion card.

software change required: Power enable is wired to SD1_DAT1 / ball C20.

EVT DVT Notes
(none) Q11F Si4435DY
(none) Q12F 2N7002W
(none) R35F 10k, 1%
(none) R36F 10k, 1%
(none) R30F 100k, 1%
(none) C95F 1.0uF, 25V, 20% X5R
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