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ralfmayr wrote on 17th Feb. 2009
I quoted your last year post, just to congratulate with you for the remarkable knowledge you have gained in a year. This will teach new comer that persevering on a subject always pay.Hi Daniel,
no, i stopped working on it, it is not possible to get it work... :-(
I solved my problem using serin/serout.
But it would be great when we exchange our know-how, so we can solve this together!
-,Ralf
Thank you for those additional I2C remarks that could be useful.
Al.
All progress began with an idea
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Yep,
last year i made my first experiments with i2cslave,
but had no time to work on it for 8 months now as
i was very busy with other things.
Hope it will help others to come faster to their target.
-,Ralf
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Hello Al,
another question:
What are the three definitions:
1. DEFINE I2C_SLOW 1
2. DEFINE I2C_HOLD 1
3. DEFINE I2C_SCLOUT 1
do?
1. => Used with LO > 8MHz and 100kHz devices
2. => Time Delay during acknowledge?
3. => Open Collector / Bipolar Clock on SCL? Dont Understand this!
So: I use PCF8575C and MAX3611 (both 400kHz devices) but both only work
correct when DEFINE I2C_HOLD 1 and DEFINE I2C_SCLOUT 1 is done.
Can you help?
Regards,
Ralf
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Hi Ralf,Originally Posted by ralfmayr
I can answer part of #3:
Open collector means the PIC has 2 states LOW where it takes the pin to ground and an open state where the pin is high impedance, so to get a high state it must have a pull up resistor to supply the power. I do not know what bipolar clock means, have not read up on this yet.
If you do not believe in MAGIC, Consider how currency has value simply by printing it, and is then traded for real assets.
.
Gold is the money of kings, silver is the money of gentlemen, barter is the money of peasants - but debt is the money of slaves
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There simply is no "Happy Spam" If you do it you will disappear from this forum.
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Yes.1. => Used with LO > 8MHz and 100kHz devices
Not Exactly, data transfer can be paused by the receiving device by holding the clock line low, so the receiving device can control the data flow. To enable this function you need the DEFINE I2C_HOLD 1 declared.2. => Time Delay during acknowledge?
Joe already answer to this point with a clear explanation. Let me add that bipolar is a device capable to pullup the lines by itself without the need of external pullup resistors3. => Open Collector / Bipolar Clock on SCL? Dont Understand this!
It is usefull to use DEFINE I2C_HOLD 1 as default since it will keep synchronized different devices connected on the I2C bus all with different internal clock.So: I use PCF8575C and MAX3611 (both 400kHz devices) but both only work
correct when DEFINE I2C_HOLD 1 and DEFINE I2C_SCLOUT 1 is done.
I don't know much about PCF8575C and MAX3611 but very likely they are bipolar devices.
Al.
All progress began with an idea
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Thank you both for the answers.
Now i understand.
So it seems always to be best to work with declaration 2 & 3 with
400 khz devices. This is what i found out yesterday.
Have nice eastern!
Regards,
Ralf
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Hi all. I need to synchronise an array from one PIC to another (one way only), so I have been working to make a simplified version of the code seen in this thread with just the bare essentials to send the array from slave to master.
It mostly works, but there is one little bug. I am sending the array over and over again - the test array is 6 bytes and I have assigned test values of 1 2 3 4 5 and 6.
On the 1st i2cread the master receives 123456. On the 2nd i2cread it gets 234561, and the third 345612. It seems that every time I do an i2cread, the following byte goes missing. The first time I get 123456, the next 1 goes into oblivion and therefore the next packet is 234561.
I know I can get around this by sending a dummy byte after the array, knowing that it will be lost, but I'd like to know why this is happening if anyone has any ideas?
Master PIC (18F2620, 40Mhz HSPLL):
Slave PIC (18F2620, 40Mhz HSPLL):Code:DEFINE OSC 40 DEFINE I2C_HOLD 1 DEFINE LCD_DREG PORTB DEFINE LCD_DBIT 0 DEFINE LCD_RSREG PORTB DEFINE LCD_RSBIT 4 DEFINE LCD_EREG PORTB DEFINE LCD_EBIT 5 DEFINE LCD_BITS 4 DEFINE LCD_LINES 2 DEFINE LCD_COMMANDUS 2000 DEFINE LCD_DATAUS 50 PAUSE 100 LCDOUT $FE,1,$FE,2 ADCON1=%00001111 CMCON=%00000111 scl VAR PORTC.3 sda VAR PORTC.4 i2c_address VAR BYTE i2c_data VAR BYTE[6] i2c_address=$0A main: I2CREAD sda,scl,i2c_address,[STR i2c_data\6] LCDOUT $FE,$80,DEC i2c_data[0] LCDOUT " ", DEC i2c_data[1] LCDOUT " ", DEC i2c_data[2] LCDOUT " ", DEC i2c_data[3] LCDOUT " ", DEC i2c_data[4] LCDOUT " ", DEC i2c_data[5] PAUSE 1000 GOTO main
Code:DEFINE OSC 40 INCLUDE "DT_INTS-18.bas" INCLUDE "ReEnterPBP-18.bas" ADCON1=%00001111 CMCON=%00000111 i2c_buffer_full VAR SSPSTAT.0 i2c_read VAR SSPSTAT.2 i2c_release_scl VAR SSPCON1.4 i2c_data VAR BYTE[6] i2c_data_index VAR BYTE dummy VAR BYTE SSPADD=$0A ' I2C Address: $0A SSPCON1=$36 SSPCON2.0=1 i2c_data[0]=1 i2c_data[1]=2 i2c_data[2]=3 i2c_data[3]=4 i2c_data[4]=5 i2c_data[5]=6 i2c_data_index=0 ASM INT_LIST macro INT_Handler SSP_INT, _i2c_int_handler, PBP, yes endm INT_CREATE INT_ENABLE SSP_INT endasm main: ' main program goes here goto main i2c_int_handler: IF i2c_read then dummy=SSPBUF IF i2c_buffer_full=0 THEN SSPBUF=i2c_data[i2c_data_index] i2c_data_index=i2c_data_index+1 IF i2c_data_index=6 THEN i2c_data_index=0 ENDIF ENDIF i2c_release_scl=1 @ INT_RETURN
Last edited by Kamikaze47; - 15th August 2010 at 23:04. Reason: spelling
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