The schematic is in several pieces in appropriate chapters of the book (pretty much one I/O block at a time). There's not much else that is different from any other Propeller board. Is there something specific you're interested in?
I'm interested into the card interface in the center. Also, it appears there is at least one other chip on the Hydra. (Can't quite tell from the pictures)
Really, I'm just looking for more ideas for stuff to add to my Propeller micro.
I'm working on my first .spin object (An Atari joystick interface on pins 4-8), and was thinking that with everything on my board already, it appears I'm approaching the functionality of the Hydra itself.
One difference between the hydra and most other designs is the way the PS/2 mouse and keyboard interfaces operate.
Most systems use a single I/O port for each clock and data line and ignore the 3,3Volt level to 5Volt level translation problem (the P/S mouse and keyboard are 5 Volt devices, but are controlled with 3,3Volt levels).
The Hydra however uses two I/O ports and a transistor circuit to do level translation, one port acts as an input, and another one as an output to the level translating transistor.
This means that "any" mouse or keyboard will work, while on the other systems in theory some mouses or keyboards might not work.
The downside is that the mouse keyboard drivers of the hydra are different from the other ones, and that the PS/2 ports of the hydra need eight I/O ports instead of just four.
Comments
Really, I'm just looking for more ideas for stuff to add to my Propeller micro.
I'm working on my first .spin object (An Atari joystick interface on pins 4-8), and was thinking that with everything on my board already, it appears I'm approaching the functionality of the Hydra itself.
Oldbit
The other chips include an EEPROM, the USB-serial adapter, and the buffer for the expansion card.
Most systems use a single I/O port for each clock and data line and ignore the 3,3Volt level to 5Volt level translation problem (the P/S mouse and keyboard are 5 Volt devices, but are controlled with 3,3Volt levels).
The Hydra however uses two I/O ports and a transistor circuit to do level translation, one port acts as an input, and another one as an output to the level translating transistor.
This means that "any" mouse or keyboard will work, while on the other systems in theory some mouses or keyboards might not work.
The downside is that the mouse keyboard drivers of the hydra are different from the other ones, and that the PS/2 ports of the hydra need eight I/O ports instead of just four.
Mahjongg