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• SDCC files ready!

  danjovic • 04/04/2016 at 09:55 • 0 comments

  I've recovered the tree of files with the SDCC compatible firmware.

• Ooops!

  danjovic • 04/01/2016 at 03:23 • 0 comments

  Sorry, uploaded wrong files to dropbox, but removed them already.

• Porting code to SDCC

  danjovic • 03/31/2016 at 17:42 • 0 comments

  After receiving feedback of Joachim from ZX81 user group that assembled the TEK I've started to porting the code to SDCC. At this time I can compile the code in SDCC running under Windows. On Linux I am still dealing with some compilation errors related to libraries but this is a matter for another log.

  The porting basically required:

  • Installing the necessary tools

  1. SDCC
  2. GPUTILS

  • Changing the type of some variables to be compatible with SDCC: chars have been replaced by uint8_t to avoid warnings and int1 have been replaced by uint8_t. I've tried to use _Bool type (from stdbool.h) but this resulted in an internal SDCC error!

  • Changing the way of defining the fuses

  //#fuses INTRC_IO, NOPROTECT, NOBROWNOUT, NOWDT, PUT 
  uint16_t __at _CONFIG configWord = _INTRC_OSC_NOCLKOUT & _CPD_OFF & _CP_OFF & _WDT_OFF & _PWRTE_ON; 

  • Replacing library functions by macros or direct accessing the registers.

  // output_low (PIN_SDA);
  
  TRIS_SDA=0; //set as output
  PIN_SDA=0;

  • Changing the delay_us funcion to reflect the time spent by the assembly code generated by the macro (it takes 4+ 9*X cycles).

  #define delay_us(x) {  uint8_t us;	\
        us = (x)*FOSC/36000000L - 4/9;\
        while(--us != 0) continue; }

  The SDCC compiler provides an estimate size of code generated: 669 instructions.

  It is almost the same size of the code generated with CCS. The difference is minimal.

• ZX81: Connections and Key Bindings

  danjovic • 06/21/2015 at 02:00 • 0 comments

  Added connections for ZX81/TK85 and key bindings for PS/2 Keyboard (ABNT Standard). Will update firmware link as soon as new bindings for keyboard is set.

  Further details available here.
  

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