Following on from the failure to get the Portfolio talking directly to the RC2014, I decided to turn my attention to the Cambridge Z88. I already have a custom RS232 to TTL serial adapter for that, and the RC2014 is all set up ready for the Portfolio at 9600 baud, so this should be straightforward…
Well, would you believe it, it was a success! The Z88 is a fantastic machine, with some good built in programs. One of those is a terminal emulator, so it really was just a case of plugging the RS232 adapter in to the RC2014, with Port B set as the primary port set at 9600 baud.
To test it properly, I typed in the test program for the LCD module https://rc2014.co.uk/modules/lcd-driver-module/ (The initial test failed, but after I plugged the LCD in correctly, everything worked fine).
Buoyed on by the success there, I decided to turn my attention back to the Portfolio. Knowing that the Z88 RS232 to TTL serial adapter worked meant I didn’t have to burn my fingers again! The only issue was that the Z88 had an almost but not quite standard pinout on the DB9
I blogged about the Z88 RS232 to TTL Serial adapter back in 2013 https://sowen.com/466/z88-to-ftdi-lead-via-max3232/ The important takeaway from this is that Gnd is on Pin7 on the Z88, although it is Pin5 on the Portfolio. It is also worth noting that Pin1 and Pin9 both carry 5v, and whilst these aren’t used in my adapter, they could break other things they are plugged in to. Pin2 and Pin3 are Tx adn Rx respectively on both the Z88 and Portfolio.
Time for a Frankenconnector to adapt them!
The other bit of unfinished business on the Portfolio was putting some terminal software on there. A copy of xterm2, as supplied on the Portfolio utility card was easy enough to find. In the past I had transferred programs to the Portfolio via the parallel adapter, however, I had recently bought an APF-01 memory card from https://apfram.com/ Whilst I had to use some propriety software on a Windows machine to copy the files on to it, it worked really well.
With everything connected up and Xterm2 started, the Portfolio and RC2014 were talking!
Again, I typed the LCD test program and sent a message to be displayed from the Portfolio to the RC2014
Although, of course, it was only as I type this blog post that I notice the Off-By-Ten error in that message! Ooops!
So, that is the Z88 and the Portfolio both ticked off of the list of computers to talk to the RC2014. Whilst the Portfolio wasn’t a complete failure before, I am really glad I revisited this and got a more satisfying result. And it has reminded me just how good both of those two machines are. I really should use them more.
