14 I/O's, pull down sips and 4 resistors to drive a 3 1/2 digit, plus icons, glass with no other support chips. The PIC directly drives the LCD... there is no LCD controller
Schematic, [very well] documented and functional assembler code, ) and a few odd files that may or may not interest you in regards to an environmental chamber setup and data collection all created with numerous pic16C74A.
Two handy features of the LCD code are that you can adjust, via a register value, the segment refresh rate. Also done via another register value, is the LCD data refresh rate. I have ran different LCD glass's from 25 to 80Hz pending on their persistence.I've got the handle on the lcd's contrast issue. I get no flicker, no shadow, and no DC.
In addition, between interrupts, this unit's reads -100 to +100 Deg C (Deg C/F toggle momentary switch included) with a + - 0.2 Deg C reading accuracy across, yes, the whole range (RTD & precision Vref). I have also left some hints on how I manipulate thermoster tables.
Also has my single pin communication output [my proprietary protocol (a spin-off of arcnet)] which send data external to a hand-held (pic also) unit for logging. This unit requires no calibration. I have also left some hints on single i/o (simplex for this example) line data comm.
Micro powered and sleep mode utility are additional features.
