Features
(4) MAX7219 8 digits, 7 Segment display modules
32 digits
Can display decimal, hex values, some text values
Each display has 8 of 7 segment LED displays
"Blue" card
3.3V interface operation
Requires both 3.3V and 5V power supplies
8 pin connector
95x95mm ODAS form factor
(4) 6-32 mounting holes
Connectors
J1 Connector
3.3V signal level
5V power to LEDs
1x8 right angle header mounted on rear of card
GND
GND
DOUT
CLK
CS
DIN
3.3V
5V
J2 (Rev 2 and higher)
+5V
DIN
CS
CLK
DOUT
GND
Programming
Arduino Programming
Arduino Drivers
Arduino Example Code
LBMAX7219X4_ADDR
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
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
class ChainableMAX7219(MAX7219):
"""
Daisy Chainable MAX7219 - driver for cascading displays based on max7219 chip_select
:param int width: the number of pixels wide
:param int height: the number of pixels high
:param ~busio.SPI spi: an spi busio or spi bitbangio object
:param ~digitalio.DigitalInOut chip_select: digital in/out to use as chip select signal
:param int baudrate: for SPIDevice baudrate (default 8000000)
:param int polarity: for SPIDevice polarity (default 0)
:param int phase: for SPIDevice phase (default 0)
"""
VHDL Code
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
Test single 8-digit modules
Test MAX7219X4 card with (4) 8-digit modules
Test Single MAX7219 Modules
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
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
"Red" Modules
Incompatible pinouts
Do not work with this card
Flipped from blue modules
Mechanicals
Revision History
Rev 2
Add 5V interface connector - J2
Card can be driven from one of the two interfaces
5V interface does not require 3.3V
+5V
DIN
CS
CLK
DOUT
GND
Rev 1
Tested/works
Requires 3.3V power and signal levels
Requires 5V power
Assembly Sheet