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Notes
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Notes
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Main selling points.
- 1 GHz ARM Cortex A8 CPU, Two PRUs, one Cortex M3
- 6 Stepper TMC2130 drivers
- 4 high power heater outputs
- 4 thermistor inputs
- 4 thermocouple inputs
- 4 USB host connectors
- 4 USR leds, perhaps one for Redeem heartbeat.
- 4 Fan outputs
- 10/100 Ethernet
- 1080p HDMI output
- Direct connection PRU on step pins
- 12-24 V input
- 4 GB, 48MByte/sec eMMC booting.
- 4 layer 0.15 mm track/gap
- Flexible PWM configurations on all MOSFETs
- CE and FCC markings
- Cost efficient, single board solution.
- Programmable current limit with temperature sens.
- Open source hardware and software (CC BY-SA / GPL 3.0)
TODO:
+ Switch to AM335x-SM
+ Switch to TMC2130
+ Power out detection.
+ Add CGND for ESD shielding
+ 4 layer
+ Switch step down and USB hub to TI components.
+ Connect VDDCR
+ Over current protection on USB? A: No...
+ Support for Thermistor and Thermocouple:
+ Calculate voltage divider for step down
+ Check trace lengths on eMMCS? A: Not relevant
+ Check if necessary to use buffer on heaters and fans!
+ Check pricing with Jason on CSD17577Q3A. Also check if gate buffer is necessary. A: No buffer.
+ Smaller footprint crystal 25MHz
+ Add to BOM.
+ Add TPS2061 for ganged over current.
+ Move LAN chip to reduce trace lenghts?
+ Find out if RTC is possible using battery. A: Dropping RTC.
+ Check bootmode!
+ Add external driver footprints.
- Add 22R resistors to USB
+ Check Current measurment resistors on TMC2130
+ Change ESD to TPD4S012
+ Add Grove connectors
+ Add temp sensor
- Verify that PMOS can be decoupled.
- Using CMOS, verify with simulation/meassurment.
+ Check which circuits are running thorugh SYS_5V, for USB.
EMI considerations:
===================
- Consider 1.8V on MII and LCDC signals.
- What is the effect of removing caps on LCDC signals?
- TVS diodes on USB needs vias for routing. Is this critical?
TO_VERIFY:
- USB self powered. OK to tie high to USB_DC?
+ Two boot modes, USB for flashing and running, EMMC for running. USB device for initial setup.
+ USR leds, do they need a transistor? A: No.
+ Perhaps higher power step down converter? A: Use TPS54202 - 2A.
+ Use Peripheral PLL for RTC? A: Yes, according to Micheal Welling
- What is the 125MHz limitation on the HDMI?
The TDA19988 handles up to 150MHz,
The LCDC looks like it can have a pixel clock up to 200 MHz.
+ Can RESET on USB HUB be connected to reset on SIP? A: Yes.
- Analog layout.
- OK to leave don't care SYSBOOT pins unconnected?
+ TUSB2046 has +/-4K ESD suppression, no additional ESD required? A: Yes.
SAVE_COST:
- Remove microSD slot. Flash/boot from USB instead.
- Remove Serial to parallel converters.
- Remove RTC crystal
- 4 stepper version? A: No, only 6.
- Use built in PWM_SS, remove PWM-chip.
- Surface mount components wherever possible. (USB connector,.. )
- Single side assembly.
- 4 layer 6 mil track/gap PCB
- Switch to 25MHz Crystal on SIP, can also be used for Ethernet?
Notes:
- pr1_pru0_pru_r30[15:0] O PRU0 Register R30 Outputs
- Removing MMC0 allows PRU direct outputs to step/dir
- Choosing Z1 and Z2 endstop inputs as direct pru pins, for fast Z-probing.
**USB HUB**
- Choosing BUSPWR low to indicate self powered mode.
- Choosing EXTMEM high to disable external EEPROM with name.
- Choosing EECLK floating since extmem is disabled.
- Choosing Ganged power mode to save Bom cost.
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- Choosing one two 0.5A and two 1A USB hosts for high power applications like Manga Screen 2
- Choosing a DNI resistor connected with CLKOUT2 to experiment with eliminating the 6MHz crystal on the USB hub.
- Choosing a DNI resistor on TST mode to experiment with 48MHz clock from SIP
- Typical $2 wifi dongle consumes 70 mA
- Typical USB thumb drive consumes 110 mA
- Max Manga Screen consumption is 700 mA
- Typical Webcam cunsumes 50 mA
- 1A is pushing it. 1.5A seems ideal.