COMMENT ON PICAXE LCD SERIAL DISPLAY AXE033, AND RTC add on AXE034

15/08/2004 NEW VERSION NOW SUPPLIED WITH I^2C access to RTC

(1) The AXE033 is a kit containing (a) a 2400 baud serial input board which executes "housekeeping" for an LCD panel with HITACHI HD4470 compatible controller chips. The kit also has mounting screws , plug. and header pins with jumper links, for configuration.

(2) The LCD panel supplied  is a non backlit 2 line by 16 characters panel.

(3) The LCD panel needs more than the 4.5 V battery pack supplied with most of our kits, to operate with a reasonable contrast ratio.

This means that to use the 4.5V battery pack or a 5V supply you will need to short out the polarity protection diode on the AXE033 board
If you want to leave  the protection diode in circuit you will need to use a 6Volt supply. To eliminate power problems AXE033 now supplied with 6V Battery pack

(4) The input  to the serial interface board is not buffered. That is if you send characters too fast for the AXE033 to handle they will be lost, or part interpreted, resulting in garbled, and strange results.

(5) PICAXE gear sends characters slow enough to not have this problem, however you must have appropriate pause statements in your program.

(6) If you use products other than PICAXE with the AXE033, you may need to "pace" your transmissions.
By "pacing" we mean you still send at 2400 Baud, but you insert a delay between characters, this is a common facility in Compilers, and embedded controller products.

(7) The RTC add on AXE034 is suitable for use only with the LCD I/F board AXE033.
The AXE033 has socket, and a crystal ready for the RTC chip, Plus a lithium battery socket. There are also header pins, and jumpers supplied for option setting.
Note the RTC (with appropriate jumper set) displays time etc on the lower line of the LCD panel. It is not possible to read time etc into another device from the RTC. However 'ALARM' may be set, and a PICAXE application software and chip / board can be arranged to receive this alarm.

(8) If you need a RTC for your non PICAXE application we have stocks of NJU6355, DS1302, DS1307, and appropriate tuning fork style crystals.