- Hahaha, I have just read this at Circuit Cellar, I hope it is not too relevant to the new IV-17 Smartsocket !
The latest news is this...
The code is mostly ported to work on the 18F26J50 (the 18F26K20 version is safely tucked away , just in case) I am finalising the real time clock functions so that the unit can keep it's own time (leap year compensation included by default !)
From a marketing perspective, what Microchip have done in giving some devices an RTCC is they have removed the EEPROM from those devices. The EEPROM is used in Smartsockets to store user defined characters.
However, the 18f26j50 is also one of the parts which allows you to write data directly to the whole flash space which means that I can reserve an area just for UDCs there. If I'm not mistaken I could also set config words which would limit the ability of the user to write to an incorrect area of flash space too which partly negates any corrupt data issues.
In terms of hardware I have managed to remove the main clock crystal
from the circuit because tests with the internal 8MHz oscillator and PLL to derive the 48MHz system clock proved that it is accurate enough to provide a reliable clock signal to the baud rate generator. Previously, some types of pic internal oscillators have lacked enough accuracy under certain circumstances, and some drift so badly with temperature changes, that a crystal was required whenever usaing the serial port.
The only crystal required now is a 32.768kHz crystal with matching loading caps, and the RTCC device has a small adjustment feature which means that to some extent it can be made self calibrating. Microchip claim an accuracy of about 3 seconds per month is achievable.
Things to do...
a) Complete the RTCC functionality
b) Create interesting ways to display four letter words
c) Finalise the Vbb power supply (+35vdc to +55Vdc)
d) PCB layout