I2CRead and USART interrupt

[Dave]

HenrikBuhl, What is the baudrate you are using? You are only acquiring 1 byte from your eeprom. I to use a 18F6720 with 2 24LC1025's, 2 active ASM driven comms @ 38.4k baud and I read 128 bytes or a page when I turn off all interrupts momentarily. The usart has a 2 byte buffer so if your baudrate is relatively low you should not loose any characters in your comm's. By the way you mention that your LCD dimming flickers. I to have an LCD on my product but I use the CCP1 & CCP2 PWM module's for the contrast as well as the backlight dimming. That way there is a continuous pwm signal to the circuitry + you have 1024 steps of backlighting.

Dave Purola,
N8NTA

[HenrikBuhl]

Hi Dave,

thanks for your reply.

My comms are running at 19,2Kbaud, and actually I am reading 20 bytes from my EEPROM in a For-Next loop.
This 20-byte-reading is done 4 times just after each other in order to get all 4 lines for the display.
Unfortunately, I can't use the CCP function for the LCD as they are used for Analog Outputs.

But! I had a breakthrough just a few minutes after submitting the original post.
Instead of reading the 20bytes in a For-Loop - reading it as a string seems to solve the problem - even without disabling interrupts.
The data are garbled anyway, but I can avoid making readouts to the display during communications.

HenrikBuhl

[Dave]

HenrikBuhl, That is the way I read the EEPROM, with the string modifier. My array is 128 bytes in size so it is easy to do page writes and string reads.

Dave Purola,
N8NTA