07-09-2020, 08:29 PM
Someone has used the 8255 PPI on a microbee. It was on the unreleased Microbee Floppy Disk Controller with 2561 USART and Real Time Clock.
The some technical documentation mentions it although it was never released because the 128K DRAM coreboard gazumped it.)
The Premium Series base board has provision for the 50 way connector although as standard it is not soldered on.
Someone finds it the easiest and most capable interface to use because it can support multiple extension devices.
It's amazing how the Beethoven works on the parallel port. The designer of it used the additional I/O port capabilities of the AY-3-8910 to cater for the lack of handshake pins available on the microbee user port. This is why the AY-3-8910 rather than the 28 pin AY-3-8912 is used. The concession is that the Beethoven driver is considerably larger, slower and more complex. You could use a similar scheme if you deem that it's worth the effort.
The Microbee user port is devoid of the BSTB and BRDY pins to operate the PIO in bidirectional mode. From the 15 pins available there was no room for them after adding in the +10V for Bee Net, PB7 for StarNet, and printer strobe pin on the Telecomputer.
Hooking up to the 50 way connector is easy stuff but you need to be careful because it's the microbee's system bus.
Just like a coreboard, the right angle connector fits on the underside of the PCB. The plastic case to be modified for fitment if not done so already.
Bit bashing I2C (or SMBus) is an easy affair and it's was the most common way to experiment with it prior to the introduction of inbuilt I2C mechanisms in microcontrollers.
As always, there's always someone to help out if you need assistance.
The some technical documentation mentions it although it was never released because the 128K DRAM coreboard gazumped it.)
The Premium Series base board has provision for the 50 way connector although as standard it is not soldered on.
Someone finds it the easiest and most capable interface to use because it can support multiple extension devices.
It's amazing how the Beethoven works on the parallel port. The designer of it used the additional I/O port capabilities of the AY-3-8910 to cater for the lack of handshake pins available on the microbee user port. This is why the AY-3-8910 rather than the 28 pin AY-3-8912 is used. The concession is that the Beethoven driver is considerably larger, slower and more complex. You could use a similar scheme if you deem that it's worth the effort.
The Microbee user port is devoid of the BSTB and BRDY pins to operate the PIO in bidirectional mode. From the 15 pins available there was no room for them after adding in the +10V for Bee Net, PB7 for StarNet, and printer strobe pin on the Telecomputer.
Hooking up to the 50 way connector is easy stuff but you need to be careful because it's the microbee's system bus.
Just like a coreboard, the right angle connector fits on the underside of the PCB. The plastic case to be modified for fitment if not done so already.
Bit bashing I2C (or SMBus) is an easy affair and it's was the most common way to experiment with it prior to the introduction of inbuilt I2C mechanisms in microcontrollers.
As always, there's always someone to help out if you need assistance.