Personally, I would just get another display. I think the easiest way to make a converter though would be to use a PIC. It should a simple enough program. And would only take the one chip. Actually, if the serial data is coming from a computer, you’d also need another chip to take care of the voltages. But I think that you could use the shift register if you really wanted to. You could disable the outputs while it’s updating if you use some kind of buffer. I wouldn’t be surprised if there is some shift register that already does this.
Most character based LCD that use a Hitachi equivalent controller have a 4 bit mode which reduces the number of pins used. For about 50$ you can buy a serial LCD. There are also some pre-programed pic chips to make your own serial LCD. Stay away from graphic LCDs. They can be very complex.
I’m working with one now, parallel, Hitachi based, I think a shift register will work but I’m not entirely sure, however the LCD only reads the data pins when you pull it’s “Enable” pin high. Serial LCDs are too expensive if you’re making a lot of something, parallels really cheap, it’s worth knowing how to use the parallel LCDs.
It has been a few years since I have done any Basic Stamp stuff with LCDs but I remember a company called Scott Edwards Electronics (http://www.seetron.com) that sells serial LCDs made to work with Basic Stamps. They sell a “LCD Serial Backpack® Interface for Alphanumeric LCDs” (http://www.seetron.com/bpk000_1.htm) that I think may be just what you are looking for.
Thats a nice solution, but a little software elbow grease and a shift register is a much simpler/cheaper solution, being that each of these is $29. That and the cost of the parallel LCD brings it up to the costs of Serial ones, somewhat defeating the purpose.
I’ve been reading up on shift registers, if you connect the clock and input pins to 2 outputs on the BS1 and use a third output for the Enable pin on the LCD, I believe it will work.
First, set the first output pin of the LSB (least significant bit) of the binary command for the LCD, then pull the clock pin on the register high, then low. That shifts the first bit in, do that 7 more times, filling in the remaining bits with zero’s if necessary, you have to do this in 8-bit chunks. Then pull enable high for 2 microseconds or so and then pull it low. Start over.
Also, you can go with 4-bit mode and use a 4-bit shifter register, but since the intent of 4-bit mode is to trade pin usage for complexity, and you won’t save anymore pins on the BS1 with it, it’s rather pointless.
anon96464947, I received your PM and we can discuss this in more detail at your leisure if you need help.
I know you have invested in the stamp but there are easier development systems to use for microcontroler learning. I posted the link to Kronos robotics. You might look here.
If you notice there is a LCD function that makes using a LCD easy. They also have a dedicated chip for implementing a serial LCD.
This summer I have mentored some high school students and have found this line to be very conductive to learning. It’s up to you but, I think you would be able to pick up the needed skills faster with a Kronos Dios chip and its matching work board.
The 40 pin chip.
These links are for a pic18F class chip. The added capabilities I believe justify the higher cost. They also have PIC 16 series chips that are much cheaper but more limited.
Walk before you run. Learn the basics and take small steps.