Assembly of the CTC board is completed. I`ve added a jumper for disabling interrupt signal if needed, and I`ve also placed a goldpin header with output and input signals from the CTC:
Channel 0: ZC/TC0 / CLK/TRG0
Channel 1: ZC/TC1 / CLK/TRG1
Channel 2: ZC/TC2 / CLK/TRG2
Channel 3: CLK/TRG2
This header will be available for any peripheral device in the system. It can also be used for cascading output from one channel to another inside the CTC itself.
Circuit schematics and board layout design:
Below We can see the whole system as it looks today. Four expansion cards are visible. From left to right: CTC board, UART Board, VGA display board and sound board:
Most of the hardware of my computer is now ready. I only have to decide on the mass storage solution. Also I`m still planning to add an I2C controller to take advantage of some interesting peripherals like RTC clock, EEPROMs, etc. In near future I`ll focus on the programming side of the project for a change. I`m going to add some UART routines (including data/program downloading / uploading ) and test some CTC interrupt functionality. I`ll try to write some form of “sound system” which could allow me to play music in the background using interrupts from CTC. I`m also planning to update the VGA Display board`s firmware to enable graphics mode of 160×100 pixels.