MAX7219X4

From Land Boards Wiki
Jump to navigation Jump to search

Tindie-mediums.png


MAX7219X4 P18550 720PX.jpg

Features[edit]

  • (4) MAX7219 8 digits, 7 Segment display modules
  • 32 digits
    • 4 rows
    • 8 digits per row
  • Can display decimal, hex values, some text values
  • Each display has 8 of 7 segment LED displays
  • Uses "Blue" LED cards
  • Rev 1 has 3.3V interface operation (J1)
    • 3.3V to 5V Level shifter
    • Requires both 3.3V and 5V power supplies
    • 8 pin connector
  • Rev 2 has 3.3V signal levels J1 (as above) or 5V signal levels (adds J2)
    • Only requires 5V for 5V operation
    • Level translator can still be installed but right connector must be used
  • 95x95mm ODAS form factor
  • (4) 6-32 mounting holes

MAX7912 8 Digs 001.jpg

Connectors[edit]

MAX7219X4 Rev2 CAD.PNG

  • Only 1 of the 2 connectors J1 or J2 can be used at a time

J1 Connector[edit]

  • 3.3V signal level
  • 5V power to LEDs
  • 1x8 right angle header mounted on rear of card
  1. GND
  2. GND
  3. DOUT
  4. CLK
  5. CS
  6. DIN
  7. +3.3V
  8. +5V

J2 (Rev 2 and higher)[edit]

  1. +5V
  2. DIN
  3. CS
  4. CLK
  5. DOUT
  6. GND

Programming[edit]

Arduino Programming[edit]

Arduino Drivers[edit]

Arduino Example Code[edit]

LBMAX7219X4_ADDR[edit]
  • Runs on Arduino in a Box
    • 3.3V signals level
    • Also requires 5V for LEDs
    • 5V on Arduino in a Box] DC Power Jack
  • 5V picked off VFILT jack
  • LBMAX7219X4_ADDR
    • void writeHexDigit(uint8_t rowVal, uint8_t colVal, uint8_t digitVal) - Write Hexadecimal digit to location
    • 8 columns, 4 rows
    • rowVal = 0 is top row in display
    • colVal = 0 = left character
LBMAX7219X4_ADDR_5V[edit]
  • Same as LBMAX7219X4_ADDR
  • Runs on 5V Arduino UNO
  • LBMAX7219X4_ADDR_5V
    • void writeHexDigit(uint8_t rowVal, uint8_t colVal, uint8_t digitVal) - Write Hexadecimal digit to location
    • 8 columns, 4 rows
    • rowVal = 0 is top row in display
    • colVal = 0 = left character
LBMAX7219X4[edit]
  • LBMAX7219X4
    • Displays Land-Boards channel intro video across the LEDs on 4 rows of 8-digits MAX7219X4 card
    • "LAND-" (first line)
    • "BOARDS" (second line)
    • "PRESENTS" (third line)
    • "CARDS...", "AND CODE" (4th line)

CircuitPython Programming[edit]

class adafruit_max7219.bcddigits.BCDDigits(spi: SPI, cs: DigitalInOut, nDigits: int = 1)[source]
Basic support for display on a 7-Segment BCD display controlled by a Max7219 chip using SPI.
Parameters
spi (SPI) – an spi busio or spi bitbangio object
cs (DigitalInOut) – digital in/out to use as chip select signal
nDigits (int) – number of led 7-segment digits; default 1; max 8

VHDL Code[edit]

instance: MAX7219
    generic map(
            devices => 2,
            intensity => (16#1#, 16#3#)
        )
    port map (
            clk => clock,
            data_vector => x"FEDCBA9876543210",
            clk_out => MAX7219_CLK,
            data_out => MAX7219_DATA,
            load_out => MAX7219_LOAD,
            reset_n => globalResetN
        );

Test[edit]

  • Test single 8-digit modules
  • Test MAX7219X4 card with (4) 8-digit modules
  • Test 3.3V operation on J1 (Rev 1 or Rev 2 or higher)
  • Test 5V operation on J2 (Rev 2 and higher)

Test Single MAX7219 Modules[edit]

SensorShield P1080453-720px.JPG

SenShld Desc MAX J1 Color
VCC VCC 1 RED
GND GND 2 BLK
D12 DATAIN 3 WHT
D10 CS 4 BRN
D11 CLK 5 YEL

Test MAX7219X4 Card 3.3V[edit]

MAX7219X4 TEST-720PX.png

Signal AiB MAX7219X4 Signal Color
GND J5-25 J1-1 GND BLK
D10 J5-21 J1-5 CS WHT
D11 J5-19 J1-4 CLK YEL
D12 J5-17 J1-6 DIN BLU
+3.3V J5-1 J1-7 +3.3V RED
VFILT J9-1 J1-8 5V ORG
  • Run Demo code
  • Displays 0-7, 8-F twice
  • Displays all 8's

Test MAX7219X4 Card 5V[edit]

MAX7219X4 P18547 TEST 720PX.jpg

Signal Shield MAX7219X4 Signal Color
GND D12-S J2-6 GND BLK
D10 D10-S J2-3 CS BRN
D11 D11-S J2-4 CLK YEL
D12 D12-3 J2-2 DIN WHT
5V D12-V J2-1 5V RED
  • Run Demo code
  • Displays 0-7, 8-F twice
  • Displays all 8's

"Red" Modules[edit]

  • Incompatible pinouts
    • Do not work with this card
    • Flipped from blue modules

RedModule Overall P1080454-720px.jpg

RedModile Left P1080456-720px.jpg

RedModule Right P1080455-720px.jpg

Mechanicals[edit]

MAX7912X4 MECHS.PNG

Revision History[edit]

Rev 2[edit]

  • Add 5V interface connector - J2
  • Card can be driven from one of the two interfaces
    • 5V interface does not require 3.3V
  • Tested / works

MAX7219 Front Rev2 3D.png

  1. +5V
  2. DIN
  3. CS
  4. CLK
  5. DOUT
  6. GND

Rev 1[edit]

  • Tested/works
  • Requires 3.3V power and signal levels
  • Requires 5V power

Assembly Sheet[edit]