ZLib

A set of library routines to drive the various hardware elements of the board. These are 'included' in the zloader monitor programme and can be used for other applications are required. This library also illustrates how to access the hardware. The code is in the zlib directory in the Git repository.

I'm continually trying to improve the comments in the code to make the libraries as usable as possible, but this is a work in progress!

• defs.asm - common hardware definitions and some macros.
• zlib.asm - an include file containing extrn declarations for the exported ZLib interface. This can be included in assembler files that want to use ZLib APIs and defines the exported interface.
• libsio.asm - A set of low level serial I/O routines for the Z80 SIO. Handles single character input/output and has an Interrupt Service Routine (ISR)that will handle input. The ISR is not installed - it's up to application code to install as necessary.
• libconin.asm - A set of higher level console input routines that provide buffered input and also implement a simple 'history' function allowing applications to record and replay previous entered lines (see GETHIST/SETHIST). If enabled then the console code interprets VT100 up/down/left/right keys to edit the current input line.
• libconout.asm - A set of higher level console output routines for printing text/numbers.
• libcmd.asm I connect a Raspberry Pi to serial port B. This library implements a simple block based command protocol to talk with the Pi. At the Pi end there's a server that waits for commands from the Z80 and sends a suitable response. There's no error correction of handshaking and the two ends can sometimes get out of sync, usually fixed by resetting the Z80. The Pi end of the protocol is implemented in tools/block.js. The protocol is documented here.
• libflash.asm - A set of low level routines that implement the Flash write algorithm. This makes writing to the onboard flash device fairly straightforward and means, for example, ZLoader can be upgraded without having to use an external flash programmer.
• libi2c.asm - low level I2C interface library. Provides initialisation, read and write byte operations
• libspi.asm - low level SPI interface library.
• librtc.asm - uses the I2C interface to talk with the real time clock (RTC) chip. Routines allow read/write for time and to the available user non-volatile storage. This is a good example of how to use the libi2c.asm interface.
• libsdc.asm - SDCard initialisation and block read/write functions. Limited right now to cards less than 2GB. Supports both SDCard 'slots'.
• libmisc.asm - Small miscellaneous hardware routines which didn't fit anywhere else. For example reading the hardware configuration switches.
• libkbd - Scanning routines for the Omega keyboard attached to the PIO card. Emulates VT100 escape codes where required.
• libvdu - Emulates a subset of VT100 control codes using the VGA text video card.
• libutils - Utility routines used within ZLib that aren't directly related to specific hardware. For example there's a string compare routine and binary to decimal conversion routines.