topic Help i2c protocol in 8-bit Microcontrollers

Help i2c protocol

Eliezer — Tue, 23 Aug 2011 02:55:04 GMT

Hello, does anyone know how to set up a communication routine i2c register but without using the microcontroller without the SDA end SCL pins, only with common pins

Re: Help i2c protocol

rocco — Tue, 23 Aug 2011 06:43:23 GMT

Hi Eliezer,

Are you asking for code to "bit-bang" the I2C protocol? If so, do you need C or assembly language? Are you using an HC08 or S08?

I you are using assembly language on an 08, I've implemented I2C as a bunch of macros (originally for the HC05). It uses a lot of in-line code to try to be fast, but it is still rather slow. Bit-timing may be an issue, as you may need to pad some macros with NOPs on the faster S08s.

Re: Help i2c protocol

Eliezer — Tue, 23 Aug 2011 21:13:03 GMT

Hello Rocco.

Yes, I need a code in C for the I2C protocol. I am using KA8 the RS08 family, but I canbe what you

have, already helps me a lot.

Grateful.

Re: Help i2c protocol

rocco — Thu, 29 Oct 2020 09:06:33 GMT

Hi Eliezer,

The KA8 is neither an S08 or an HC08, but an RS08, so the assembly language code may not work (I have never used an RS08, as I consider them brain-damaged.

But here is my I2C macro file anyway. IYou use it by stringing I2C commands together, such as this routine from an HC08 project:

;
;
; Read all just the motor limit parameters from the EEPROM,
; from the page pointed to by 'ParameterPage'. The parameters
; we need to read are 'MinPosition' and 'MaxPosition'.
;
ParamLoadLimits:
 EE_READ ParameterPage,#(MinPosition-EEP_Start),EER_ERR2
    ;node page, byte in EEPROM, error exit
;
 EE_BYTE_IN  ;get a data byte from EEPROM
 EE_ACK   ;ACK it to continue
 sta MinPosition ;store the data byte
;
 EE_BYTE_IN  ;get a data byte from EEPROM
 EE_ACK   ;ACK it to continue
 sta MinPosition+1 ;store the data byte
;
 EE_BYTE_IN  ;get a data byte from EEPROM
 EE_ACK   ;ACK it to continue
 sta MinPosition+2 ;store the data byte
;
 EE_BYTE_IN  ;get a data byte from EEPROM
 EE_ACK   ;ACK it to continue
 sta MaxPosition ;store the data byte
;
 EE_BYTE_IN  ;get a data byte from EEPROM
 EE_ACK   ;ACK it to continue
 sta MaxPosition+1 ;store the data byte
;
 EE_BYTE_IN  ;get a data byte from EEPROM
 EE_NAK   ;NAK it to make it stop
 sta MaxPosition+2 ;store the data byte
;
; done reading bytes
;
 EE_STOP   ;and issue the stop sequence.
;
 jsr SetLimits ;update the DSP on the situation
 clc   ;clear carry
 rts   ;return happy with carry clear
;
;
; EEPROM error routine for a Read of limit parameters.
;
EER_ERR2:
 EE_STOP   ;drop the EEPROM
 ErrLog E_EEPRMread ;"EEPROM Read Error"
 sec   ;set carry
 rts   ;return empty handed with carry set

Re: Help i2c protocol

rocco — Wed, 24 Aug 2011 01:31:48 GMT

And here is the macro file.