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136 lines
4.3 KiB
Markdown
136 lines
4.3 KiB
Markdown
# Glorified Gimletlet (Gimletlet rev2) User Guide
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## General
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- Locations on the board will be referenced in terms of compass directions.
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There is a North arrow in the northwest corner of the board next to J14.
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- All I/O is 3.3V. If you want 5V or 1.8V you will need an external level
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shifter.
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## Power
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You have three options.
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**Note:** early series Gimletlet2 boards are missing C1/C2, which are necessary
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for the on-board regulator to operate. If your board is missing these parts (in
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the northeast corner) then you must provide 3.3V from an external supply
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(below).
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### Using the barrel jack
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J1 is a barrel jack that can accept power from the 12V adapters distributed with
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the Gemini bringup boards. This is converted to 3.3V by the regulator U1.
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- JP1 (USE JACK), northeast corner: closed
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- JP2 (USE REG), west of that: closed
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- No other power supply attached.
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### Providing off-board 5-12V
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To provide off-board power in the range of 5-12V for use by the onboard
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regulator, you can open JP1 (USE JACK, northeast corner) and attach a power lead
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to its eastern pin. Remember to also connect ground to your supply, through one
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of the ground posts or through the southern row of J7/J8 (northeast of SP U2).
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- JP2 (USE REG, west of JP1) must be closed for this to work.
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- Barrel jack J1 is out of the circuit with JP1 open, so connect it or don't, it
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doesn't matter.
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### Providing off-board 3.3V
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To bypass the onboard regulators entirely, you can provide 3.3V from an external
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supply. If you have an early series board that is missing C1/C2, this is your
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only option.
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- JP2 (USE REG, northeast corner just south of I2C2 header J9): open.
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- JP1 (USE JACK): doesn't matter
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Apply external power either on the northern pin of JP2, or through any pin on
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the north row of J8 (marked 3v3s, northeast of SP U2).
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## Programming and recovery
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To program the SP, connect an STLink V3 to J15 (SWD, southeast of SP U2) and
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apply power to the board through one of the methods above.
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SW1 (RESET, southeast of that) resets the SP.
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If you want to force the chip into bootloader, e.g. to recover from a really
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corrupt firmware image or because you're having a hard time attaching GDB with
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the chip in a low-power mode, close JP3 (ROM BOOT, east of SP U2). Remember to
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open it again later, or the chip will never leave the bootloader.
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## Blinkies
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All LEDs are to the south of the big IC U2. All are active high.
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- D1 - SP PG2
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- D2 - SP PG3
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- D3 - SP PG4
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- D4 - SP PG5
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## PMOD connectors
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The board sports ten PMOD-compatible connectors of four types.
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### UARTs
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UART connectors use the standard PMOD "type 3" pinout.
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- J12 (southeast corner): USART1. TX=B6, RX=B7, RTS=A12, CTS=A11.
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- J13 (east edge): USART2. TX=D5, RX=D6, RTS=D4, CTS=D3.
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- J14 (northwest corner): UART7. TX=E8, RX=E7, RTS=E9, CTS=E10.
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### I2C
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I2C connectors use the standard PMOD "type 6" pinout.
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- J9 (north edge): I2C2. SDA=F0, SCL=F1, SMBA=F2, RESET=F3.
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- J10 (south edge): J2C3. SDA=C9, SCL=A8, SMBA=A9, RESET=A10.
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- J11 (south edge): I2C4. SDA=F15, SCL=F14, SMBA=F13, RESET=G0.
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### SPI
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SPI connectors use the standard PMOD "type 2A" pinout.
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- J3 (southeast): SPI3. MISO=C11, MOSI=C12, SCK=C10, CS=A15, INT=D0, RESET=D1.
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- J4 (southwest): SPI4. MISO=E13, MOSI=E14, SCK=E12, CS=E11, INT=E15, RESET=B10.
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- J5 (northeast): SPI6. MISO=G12, MOSI=G14, SCK=G13, CS=G8, INT=G11, RESET=G15.
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### QuadSPI
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The QuadSPI connector uses a variant on the SPI pinout, since there is no
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standard PMOD QuadSPI pinout.
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J2 (north edge): QSPI1.
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- CLK: F10
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- IO0: F8
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- IO1: F9
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- IO2: F7
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- IO3: F6
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- CS: G6
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F4/F5 are routed to the QSPI connector as extra signals (e.g. write protect,
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hold, reset).
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## Hacking connectors
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Four connectors on the board are intended for random unforeseen uses. They are
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labeled on the silkscreen.
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- J7: 3x 12V (north row) and GND (south row)
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- J8: 3x 3v3 (north row) and GND (south row)
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- J16: ground, 3v3, and seven free GPIO
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- J17: ground, 3v3, and five free GPIO
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## NIC connector and test points
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The NIC connector (J6, west edge) is a Hirose DF9 connector intended to support
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modular network interface boards. It provides access to RMII, SPI4, and I2C4.
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This means that certain NIC cards installed at J6 may interfere with accessories
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plugged into J4 (SPI4) and J11 (I2C4). Be warned.
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The NIC pinout is a bit long to type here but it's in the schematic.
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