2009/2/22 Sebastien Lelong <[email protected]>: > So, not a big deal, we'll build and specify our own. Joep seems to have a > ideas about how such controller should do.
I have. And to document, share and get your input - this is where I am now: - I want an application that uses one pin on the master and interfaces to a lcd display. I intend to use standard async serial comms for this. - the app is optimised to controle the lines, but is not aware of the display logic. - A char display uses 6 or 10 lines. - A graphical display (at least the one i have) uses 13 lines. But also reads back from the display, so probably won't work with this sollution. - The setup will use a basic dataset of 7 bits, leaving the highest bit 0. - For 4-bit mode, this means every nibble can be transered in one byte; two bytes are needed for each full cmd or data write. - In 8-bit mode, the 7 bit will contain the lowest 7 bits of the dataport. The 'slave' will have a feature that automaticly generates the enable pulse. - When the high-bit is set, the remaining 7 bits are used for special purposes, like turning the autmatic enable pulse on and off, set the remaining 3 IO lines etc. What and how exactly will become clear as we go. - Since one byte (in 8-bit mode) gets a standard delay of 40us, which is 25 char/ms or 250kbps. So speeds up to 115k2 can be supported without a problem. - Of course some commands take more time. But since the controler is not aware of this, the lib should take care of this (and it does already :) - I am not use about i2c. We could use the same strategy (it's just processing a byte stream) but there are alternatives, like the dogm interface, i2c IO chips (they sell for less then a pic, see Wouter's shop). And we could also use a protocol that is optimised for i2c. Joep PS I had an other look at the dogm character displays / st7036 controller and learned that 'serial' means SPI and uses 4 lines. i2c is like expected and uses 2 lines (and can be shared with other slaves). If this is correct and it is hd44780 compatible, controlling the dogm display will be mainly a task of linking available libs (i2c master and hd44780). --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "jallib" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/jallib?hl=en -~----------~----~----~----~------~----~------~--~---
