using I2c of RAMPS 1.4

[pankajbadatia]

Hi all I want to know how can i connect RAMPS as masster and other arduino as slave using I2c communication.
which code should i edit .
my slave address is 0x08
start bit 0x01
command bit 0x02
stop bit 0x17

[thinkyhead]

With #3258 we added an i2c bus feature, which exists in RC6 and the current RCBugFix. Enable EXPERIMENTAL_I2CBUS in Configuration_adv.h and you can use it to experiment with sending and receiving bytes using GCode commands.

[pankajbadatia]

Thank you .. I did it but i have confusion between sending hex value and byte or char

[jbrazio]

What is the confusion ?

[pankajbadatia]

address is in hex when

M155 A8 // slave address
M155 B1 // start bit
M155 B2 // command
M155 B23 // stop bit
M155 S1 // send 

it doesn't work . Is this correct way to send command??

[pankajbadatia]

 * ; Example #1
 * ; This macro send the string "Marlin" to the slave device with address 0x63
 * ; It uses multiple M155 commands with one B<base 10> arg
 * M155 A63  ; Target slave address
 * M155 B77  ; M
 * M155 B97  ; a
 * M155 B114 ; r
 * M155 B108 ; l
 * M155 B105 ; i
 * M155 B110 ; n
 * M155 S1   ; Send the current buffer

I am reffering this

[jbrazio]

It uses multiple M155 commands with one B<base 10> arg

M155 B77 the 77 is ASCII "M" in decimal (base 10).
In your case you only need to convert M155 B23 (base 16) to M155 B35 (base 10).

[thinkyhead]

confusion between sending hex value and byte or char
you only need to convert M155 B23 (base 16) to M155 B35

@pankajbadatia
Actually, it looks like you did the right conversions. 0x17 is 23 decimal.
What result do you expect when you send 8: 1, 2, 23?

…address is in hex when…

All values are expressed in decimal. So in your second example A63 should be A99.

; Example #1
; This macro send the string "Marlin" to the slave device with address 0x63
; It uses multiple M155 commands with one B<base 10> arg
M155 A99  ; 0x63 Target slave address
M155 B77  ; M
M155 B97  ; a
M155 B114 ; r
M155 B108 ; l
M155 B105 ; i
M155 B110 ; n
M155 S1   ; Send the current buffer

[jbrazio]

Scott, that's the example from the Configuration_adv.h.

[pankajbadatia]

Does the ramp accept address in hex or decimal ??

[pankajbadatia]

/* Start and end of packet markers These are
start of packet SOP
and end of packet EOP
of different microprocessor which i am using*/

#define PACKET_SOP (0x01u)
#define PACKET_EOP (0x17u)

/* any one can be used Commands set */
#define CMD_SET_OFF (0u)
#define CMD_SET_RED (1u)
#define CMD_SET_GREEN (2u)
#define CMD_SET_BLUE (3u)

Then which commands should i send

[thinkyhead]

Scott, that's the example from the Configuration_adv.h.

And it's wrong, alas.

[thinkyhead]

Does the ramp accept address in hex or decimal?

The M155 feature needs the address (A) to be specified in decimal — only digits from 0-9 are acceptable in GCode parameters.

[thinkyhead]

Then which commands should i send ?

I'm just guessing here, but it looks like you have the right idea…

M155 A8  ; slave addr
M155 B1  ; PACKET_SOP
M155 B0  ; all off first
M155 B1  ; red
M155 B2  ; +green = yellow
M155 B23 ; PACKET_EOP
M155 S1  ; <send>

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