Code:
'****************************************************************
'* Name : MAX7219_8-Digit_7-Segment_Demo.BAS *
'* Author : Roberts *
'* Notice : Copyright (c) 2021 Copyright (c) 2019 *
'* : All Rights Reserved *
'* Date : 10/6/2021 *
'* Version : 1.0 *
'* Notes : Developed on Microchip Curiosity Board with *
'* : PIC16F183456 uC and the HW-179 8-digit/7-segment *
'* : display driven by the MAX7219 driver via 3-wire *
'* : SPI interface, set to operate at 5 VDC. *
'****************************************************************
'
' This brief demo program writes the digits 0 thru 9 and "-" to the HW-179 8-digit 7-segment LED display based on the
' MAX7219 interface driver. The code includes the initialization sequence that (a) sets the decode mode to BCD,
' (b) sets the LED intensity to half-scale (8/16), (c) sets all 8 digits active, and (d) activates the display.
' After initialization, the code sets the test mode active for 1 second (e.g., all digits and all segments lit). Then
' all digits are cleared, and counting begins with the right-hand most digit. Each digit counts from 0 to 9 and then
' "-", and the counting progresses to the left one digit at a time. Once all 8 digits are showing "-", the program
' cycles back to clearing the display and repeating.
' Data is sent to the display using PBP's SHIFTOUT command. The code demonstrates how these 16-bit address + data
' commands can be constructed as either a single 16-bit constant, by an 8-bit variable + 8-bit constant, and by two 8-bit
' variables. While the MAX7219 data registers are blanked upon power on, a microcontroller reset requires a procedure
' that writes 0x0F to all 8 digits in order to blank the digits.
'
'****************************************** PIC16F18346 Initialization *************************************************
'************************************** Configuration File for the PIC 16F18346 ****************************************
#CONFIG
__config _CONFIG1, _FEXTOSC_OFF & _RSTOSC_HFINT32 & _CLKOUTEN_OFF & _CSWEN_ON & _FCMEN_ON
__config _CONFIG2, _MCLRE_ON & _PWRTE_OFF & _WDTE_ON & _LPBOREN_OFF & _BOREN_ON & _BORV_LOW & _PPS1WAY_OFF & _STVREN_ON & _DEBUG_OFF
__config _CONFIG3, _WRT_OFF & _LVP_OFF
__config _CONFIG4, _CP_OFF & _CPD_OFF
#ENDCONFIG
@ ERRORLEVEL -306 ; turn off crossing page boundary message
OSCFRQ = 000100 ' Set internal osc to 16MHz
DEFINE OSC 16 ' Tell PBP that the device will clock at 16MHz (necessary for uSec pauses used in bit-banging)
ANSELA = 000000 ' PortA all digital / available pins are A0 through A5 (6 I/O's)
TRISA = 000000 ' PortA all outputs
'
'************************** Initialization and Variable Declarations *****************************************
'
' SPI signals use LATx.x assignments to prevent read/modify/write conflicts on a single I/O port
CS Var LATA.2 ' uC chip select output pin
SCK Var LATA.4 ' uC clock out pin
SI Var LATA.5 ' uC data out / LCD Data in pin
'
'
i VAR WORD ' loop counter variable
j VAR byte ' loop counter variable
CS = 1 ' Disable SPI device select CS for OLED
'
'************************* Initialize the display parameters by sending 16-bit constants **********************
' (See MAX7219 spec sheet for tables listing full range of initialization values)
CS = 0
SHIFTOUT SI, SCK, 1, [$0F01\16] 'Test display - illuminate all segments & all digits
CS = 1
PAUSE 1000 'hold for 1 second
CS = 0
SHIFTOUT SI, SCK, 1, [$0F00\16] 'Return to normal display mode
CS = 1
PAUSE 1000 'Pause 1 second
CS = 0
SHIFTOUT SI, SCK, 1, [$09FF\16] 'Set decode mode for BCD
CS = 1 '($0900 for no decoding - see MAX7219 spec sheet)
PAUSE 10
CS = 0
SHIFTOUT SI, SCK, 1, [$0A07\16] 'Set display intensity to half scale
CS = 1 '($0A00 for minimum brightness / $0A0F for maximum brightness)
PAUSE 10
CS = 0
SHIFTOUT SI, SCK, 1, [$0B07\16] 'All 8 digits active
CS = 1 '($0B01 for only digit 1 active - see MAX7219 spec sheet)
PAUSE 10
CS = 0
SHIFTOUT SI, SCK, 1, [$0C01\16] 'Activate display
CS = 1 '($0C00 for powering down the display - see MAX7219 spec sheet)
PAUSE 10
'********************************************* Main Program **********************************************************
main:
For i = 1 to 8 'Clear all 8 digit registers to blank
CS = 0
Shiftout SI, SCK, 1, [i,$0F] 'Clear each digit "i" by sending the blank character constant 0x0F
CS = 1
Pause 10
Next i 'hold the display blank for 1 second
Pause 1000
For j = 1 to 8 'the variable j is the 8-bit digit address register
For i = 0 to 10 'the variable i is the 8-bit data register
CS = 0
SHIFTOUT SI, SCK, 1, [j,i] 'Display 0 through 9 in digit 1 position (r/h most digit)
CS = 1
PAUSE 500 'pause 1/2 second for counting
Next i
Next j
Pause 2000 'hold the display for 2 seconds
Goto main
HW-179 8-Digit 7-Segment LED Display (MAX7219 Driver)
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Originally Posted by richard
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