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jartur32
Joined: 24 Feb 2014
Posts: 10
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| I2C 18f2550 master received string - 16f1503 slave (SOLVED) |
 Posted: Fri Mar 21, 2014 1:36 pm |
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Hi all 
I'm having a problems when using I2C in one project.
In my project, I receive a data string from i2c master to slave perfect, but I can not send a request to return data from the master to the slave, which only need to return a string to the master pic. I've only gotten back a single character with no problem.
I used PIC18F2550 master and 16f1503 slave.
Thank so much !
Master send code 18f2550
| Code: |
#define SDA_PIN PIN_B0
#define SCL_PIN PIN_B1
#use I2C(MASTER, SDA=SDA_PIN, SCL=SCL_PIN, FORCE_HW, FAST)
#define lenbuff_buffer_i2c_incoming 10
char buffer_i2c_incoming[lenbuff_buffer_i2c_incoming];
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void main()
{
i2c_start(); // ATTENTION Slaves!
i2c_write(Slave_1_ADDR + 1); // adding 1 to the address tells the slave that you will be reading data from it
buffer_i2c_incoming[0] = i2c_read(1); // read data from the slave (a '1' is default and sends and ACK(acknowledge) to the slave upon successful
buffer_i2c_incoming[1] = i2c_read(1); // read data from the slave (a '1' is default and sends and ACK(acknowledge) to the slave upon successful
buffer_i2c_incoming[2] = i2c_read(1); // read data from the slave (a '1' is default and sends and ACK(acknowledge) to the slave upon successful
buffer_i2c_incoming[3] = i2c_read(1); // read data from the slave (a '1' is default and sends and ACK(acknowledge) to the slave upon successful
buffer_i2c_incoming[4] = i2c_read(1); // read data from the slave (a '1' is default and sends and ACK(acknowledge) to the slave upon successful
buffer_i2c_incoming[6] = i2c_read(0); // a '0' tells the slave that reading time is over and the Master doesn't want any more data
i2c_stop(); // release the bus
delay_ms(1000);
}
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Slave received code 16f1503
| Code: |
#define SCL_i2c PIN_C0
#define SDA_i2c PIN_C1
#USE I2C(SLAVE, sda=SDA_i2c, scl=SCL_i2c, ADDRESS=0x10, FORCE_HW, FAST)
#define lenbuff_string_i2c_return 7
char string_i2c_return[lenbuff_string_i2c_return] = {'1','2','3','4','5','6','\0'};
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#INT_SSP
void ssp_interrupt()
{
char state,incoming;
state = i2c_isr_state();
if(state < 0x80)//Master send data
{
incoming = i2c_read();//An array will be needed to store data if more than one byte is transferred
if (state == 0)
count_i2c_data = 0; //here need to read but not store
else
{
string_i2c[count_i2c_data++] = incoming;
if (incoming==0)
FLAG_have_string=TRUE;
}
}
else
if(state == 0x80)//Master need data
{
for (int8 j = 0; j <= strlen(string_i2c_return); j++) // for
i2c_write(string_i2c_return[j]); // send actual data
}
}
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Last edited by jartur32 on Sat Mar 22, 2014 6:59 pm; edited 2 times in total |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Fri Mar 21, 2014 2:44 pm |
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Are you aware that you have a previous, from Feb. 23, 2014, where you
ask the exact same question and Ttelmah solved it for you with sample
code, and you tested it and declared the problem solved ?
http://www.ccsinfo.com/forum/viewtopic.php?t=51961 |
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jartur32
Joined: 24 Feb 2014
Posts: 10
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| Posted: Fri Mar 21, 2014 3:11 pm |
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hi pcm programmer
This is a new problem, I can not make the pic slave responds to the pic master with a string, and the pic-master receives the string data to show value on LCD. I've only gotten back a single character to the master. il change the topic name to one more correct and diferent
Last edited by jartur32 on Fri Mar 21, 2014 3:25 pm; edited 1 time in total |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Fri Mar 21, 2014 3:24 pm |
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Right, but in your new code here you are attempting to send the whole
string in one pass, inside the isr. Try it with the slave sending one byte
per #int_ssp interrupt.
Also, you are declaring locals inside the code. This isn't really supported
in CCS. I mean this:
You should declare locals at the start of the function. |
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jartur32
Joined: 24 Feb 2014
Posts: 10
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| Posted: Sat Mar 22, 2014 6:58 pm |
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Thank pcm programmer
Final code
Master
| Code: |
#define SDA_PIN PIN_B0
#define SCL_PIN PIN_B1
#use I2C(MASTER, SDA=SDA_PIN, SCL=SCL_PIN, FORCE_HW, FAST)
#define ADDR 0x10
#define lenbuff_i2c 6
char buffer_i2c[lenbuff_i2];
void read_i2c(void)
{
i2c_start(); // ATTENTION Slaves!
i2c_write(ADDR); // address slave
i2c_write(0x00); // address data 0
i2c_start(); // ATTENTION Slaves!
i2c_write(ADDR + 1); // Adding 1 to the address reading data
buffer_i2c[0] = i2c_read(1); // Read data from the slave
buffer_i2c[1] = i2c_read(1); // Read data from the slave
buffer_i2c[2] = i2c_read(1); // Read data from the slave
buffer_i2c[3] = i2c_read(1); // Read data from the slave
buffer_i2c[4] = i2c_read(0); // A '0' Master doesn't want any more data
buffer_i2c[5] = '\0';
i2c_stop();
}
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Slave
| Code: |
#define SCL_i2c PIN_C0
#define SDA_i2c PIN_C1
#USE I2C(SLAVE, sda=SDA_i2c, scl=SCL_i2c, ADDRESS=0x10, FORCE_HW, FAST)
int8 j=0;
int1 FLAG_have_string = FALSE;
#define lenbuff_string_i2c 7
char string_i2c[lenbuff_string_i2c];
#define lenbuff_string_i2c_return 6
char string_i2c_return[lenbuff_string_i2c_return];
#INT_SSP
void ssp_interrupt()
{
char state,incoming;
state = i2c_isr_state();
if(state < 0x80)//Master envia datos
{
incoming = i2c_read();//An array will be needed to store data if more than one byte is transferred
if (state == 0)
{
count_i2c_data = 0; //here need to read but not store
j = 0;
}
else
{
string_i2c[count_i2c_data++] = incoming;
if ( incoming == 0 )
FLAG_have_string=TRUE;
}
}
if(state >= 0x80)//Master pide datos
{
i2c_write(string_i2c_return[j++]); // send actual data
}
}
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