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The Puma
Joined: 23 Apr 2004
Posts: 227
Location: The Netherlands
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| Problem with MAX7221 and driving leds |
 Posted: Sat Mar 11, 2006 10:51 am |
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I trying to drive a led connected on pin 2 (DIG0) and pin 14 (SEG A) on the max7221 with following program, but i can't get to work
Please help me
| Code: | #include <18F4620.h>
#use delay(clock=20000000)
#fuses HS,NOWDT,NOBROWNOUT,NOPUT,NOLVP,DEBUG,NOSTVREN,NOPROTECT
#include <max7221.h>
void main() {
setup_spi(SPI_MASTER | SPI_H_TO_L | SPI_CLK_DIV_16);
max7221_init();
while(true) {
max7221_put(DIGIT_0,0x00);
delay_ms(50);
max7221_put(DIGIT_0,0x01);
delay_ms(50);
}
}
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| Code: | #ifndef MAX7221_CS
#define MAX7221_CS PIN_C0
#define MAX7221_CLK PIN_C3
#define MAX7221_DOUT PIN_C4
#define MAX7221_DIN PIN_C5
#endif
// Register address map
#define NO_OP 0x00 // Used when cascading max7221s
#define DIGIT_0 0x01 // Digit 0 register
#define DIGIT_1 0x02 // Digit 1 register
#define DIGIT_2 0x03 // Digit 2 register
#define DIGIT_3 0x04 // Digit 3 register
#define DIGIT_4 0x05 // Digit 4 register
#define DIGIT_5 0x06 // Digit 5 register
#define DIGIT_6 0x07 // Digit 6 register
#define DIGIT_7 0x08 // Digit 7 register
#define DECODE_MODE 0x09 // Decode mode register
#define INTENSITY 0x0A // Intensity register
#define SCAN_LIMIT 0x0B // Scan-limit register
#define SHUT_DOWN 0x0C // Shutdown register
#define DISPLAY_TEST 0x0F // Display-test register
// Shutdown register
#define SHUTDOWN_MODE 0x00 // Shutdown mode
#define NORMAL_MODE 0x01 // Normal mode
// Decode-mode register
#define NO_DECODE_DIGITS_7_0 0x00 // No decode for digits 7-0
#define CODE_B_DECODE_DIGIT_0 0x01 // Code B decode for digit 0
#define CODE_B_DECODE_DIGITS_3_0 0x0F // Code B decode for digits 3-0
#define CODE_B_DECODE_DIGITS_7_0 0xFF // Code B decode for digits 7-0
// Intensity register
#define DUTY_CYCLE_1 0x00 // Intensity min
#define DUTY_CYCLE_2 0x01
#define DUTY_CYCLE_3 0x02
#define DUTY_CYCLE_4 0x03
#define DUTY_CYCLE_5 0x04
#define DUTY_CYCLE_6 0x05
#define DUTY_CYCLE_7 0x06
#define DUTY_CYCLE_8 0x07
#define DUTY_CYCLE_9 0x08
#define DUTY_CYCLE_10 0x09
#define DUTY_CYCLE_11 0x0A
#define DUTY_CYCLE_12 0x0B
#define DUTY_CYCLE_13 0x0C
#define DUTY_CYCLE_14 0x0D
#define DUTY_CYCLE_15 0x0E
#define DUTY_CYCLE_16 0x0F // Intensity full
// Scan-limit register
#define DISPLAY_DIGIT_0 0x00 // Display digit 0
#define DISPLAY_DIGITS_01 0x01 // Display digits 0 & 1
#define DISPLAY_DIGITS_012 0x02 // Display digits 0 1 2
#define DISPLAY_DIGITS_0123 0x03 // Display digits 0 1 2 3
#define DISPLAY_DIGITS_01234 0x04 // Display digits 0 1 2 3 4
#define DISPLAY_DIGITS_012345 0x05 // Display digits 0 1 2 3 4 5
#define DISPLAY_DIGITS_0123456 0x06 // Display digits 0 1 2 3 4 5 6
#define DISPLAY_DIGITS_01234567 0x07 // Display digits 0 1 2 3 4 5 6 7
// Display-test register
#define NORMAL_OPERATION 0x00 // Normal operation
#define DISPLAY_TEST_MODE 0x01 // Display-test mode, all leds on
void max7221_put(int addr,int data) {
output_low(MAX7221_CS);
spi_write(addr);
spi_write(data);
output_high(MAX7221_CS);
}
void max7221_init() {
max7221_put(DECODE_MODE,NO_DECODE_DIGITS_7_0);
max7221_put(SCAN_LIMIT,DISPLAY_DIGIT_0);
max7221_put(SHUT_DOWN,NORMAL_MODE);
max7221_put(DISPLAY_TEST,NORMAL_OPERATION);
max7221_put(INTENSITY,DUTY_CYCLE_8);
}
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rberek
Joined: 10 Jan 2005
Posts: 207
Location: Ottawa, Canada
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| Posted: Sun Mar 12, 2006 9:03 am |
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You have to ask a SPECIFIC question here. Just stating that it doesn't work gives 0 information to any potential helper.
What did you want it to do? What is it doing instead? Why are you hooking up a single LED to a 7.5 segment LED driver?
As has been pointed out many times before:
1) Ask Specific questions. If you don't that means we all have to guess at the billion ways a hardware/firmware/software project can fail. No one will do this since it is a waste of our time.
2) Your last post went unanswered (AFAIK) because you basically pasted a pointer to a datasheet and asked people to get you started on it. Get yourself started on it and when you run in to a problem with your code then ask a specific question. Unless someone on here is more kindhearted than most and has designed one of those bits into a project of theirs, no one is going to go off and read a spec for you and write code.
Maybe its not my place to say this, and maybe it sounds harsh, but it needs to be said again. Its clearly term project season in high schools, colleges and universities around the globe, because there are alot of posts lately asking the forum members to do their project for them.
[/vent_mode] |
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