giomba/nes-proj
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity
8c3fa17ec0
nes-proj/cpu/6502
History
Oliver Schmidt a5d7a06027 Enhanced Ethernet drivers. 
Made Ethernet drivers easier to consume by assembly programs.
* Replaced function pointers with JMP instructions.
* Provide return values additionally via Carry flag.

Reset Ethernet chips on initialization.
Both for the CS8900A and the W5100 the data sheets just say that
the RESET bit is automatically cleared after the RESET. This may
be interpreted in two ways:
1) There's no need to be afraid of reading the RESET bit as 1 and
unintentionally trigger a RESET by writing it back after ORing in
some other bit.
2) The RESET process isn't complete before the RESET bit hasn't
become 0 again.
It's impossible for me to empirically falsify the latter option
as the drivers are supposed to work on faster machines than the
ones I have access to. And if the RESET process includes things
like oscillators then the time to complete the RESET could differ
even between multiple exemplars of the same chip. Therefore I
opted to presume the latter option.
However that means a non-exsistent chip may cause an infinite
loop while waiting for the RESET bit to be cleared so I finally
added code to detect the presence of the Ethernet chips. There's
a risk of a chip being locked up in a way that makes the detection
fail - and therefore the RESET not being performed. This catch-22
needs to be solved by the user doing a hard RESET.
2014-06-12 22:56:35 +02:00
..
ctk Add somewhat more support to use different mouse drivers. 2014-01-17 23:45:59 +01:00
ethconfig Adjusted base address to final product. 2014-02-26 20:23:09 +01:00
ipconfig Updated include paths for the moved files under net/ 2014-01-26 23:20:23 +01:00
lib Updated include paths for the moved files under net/ 2014-01-26 23:20:23 +01:00
net Enhanced Ethernet drivers. 2014-06-12 22:56:35 +02:00
sys A massive all-tree automated update of all double inclusion guard #defines that changes from using two underscores as a prefix, which are reserved, to not using two underscores as a prefix 2013-11-24 20:20:11 +01:00
6502def.h Added UIP_CONF_LLH_LEN. 2014-01-17 22:07:03 +01:00
Makefile.6502 Build static Ethernet drivers directly from source. 2014-06-09 23:35:19 +02:00
Makefile.customrules-6502 Build static Ethernet drivers directly from source. 2014-06-09 23:14:11 +02:00
README.md Build static Ethernet drivers directly from source. 2014-06-09 23:14:11 +02:00

README.md

6502

The cpu/6502/ directory is used for targeting 6502-based machines using the cc65 compiler http://cc65.github.io/cc65/.

The Contiki network configuration for 6502-based targets is loaded from a binary configuration file (by default named contiki.cfg). It has the following format:

  • Bytes 1 - 4: IP Address (HiByte first)
  • Bytes 5 - 8: Subnet Mask (HiByte first)
  • Bytes 9 - 12: Default Router (HiByte first)
  • Bytes 13 - 16: DNS Server (HiByte first)
  • Bytes 17 - 18: Ethernet card I/O address (LoByte first !)
  • Bytes 19 - xx: Ethernet card driver name (ASCII / PETSCII)

An online Contiki configuration file generator is available at two sites:

The build for 6502-based machines includes the 'disk' make goal which creates a bootable floppy disk image containing the project binary, a sample configuration file and the Ethernet card drivers.

The build for 6502-based machines supports so-called high-level configuration macros which allow to customize Contiki on a per-project basis. They are set in form of a comma-separated list as value of the make variable DEFINES on the make command line. The value of DEFINES can be saved with the 'savedefines' make goal. The values of the high-level configuration macros are not tracked by the build so a manual rebuild is necessary on any change. The following high-level configuration macros may be set:

  • MTU_SIZE

    • Default: 1500
    • Purpose: Set the Maximum Transfer Unit size.

  • CONNECTIONS

    • Default: 10
    • Purpose: Set the maximum number of concurrent TCP connections.

  • ETHERNET

    • Default: N/A
    • Purpose: Link Ethernet driver statically instead of loading it dynamically using the network configuration file.

  • WITH_LOGGING

    • Default: 0
    • Purpose: Have log_message() and UIP_LOG() write messages to the screen.

  • WITH_BOOST

    • Default: 0
    • Purpose: Significantly improve troughput on sending full sized packets by splitting them thus workarounding the "delayed acknowledge".

  • WITH_FORWARDING

    • Default: 0
    • Purpose: Enable support for the 'IP forwarding' packet driver.

  • WITH_CLIENT

    • Default: 0
    • Purpose: Enable support for outgoing TCP connections.

  • WITH_DNS

    • Default: 0
    • Purpose: Enable UDP support and initialize resolver process on startup.

  • WITH_GUI

    • Default: 0
    • Purpose: Initialize the the CTK process on startup.

  • WITH_MOUSE

    • Default: 0
    • Purpose: Enable CTK mouse support and load a mouse driver.

  • WITH_ARGS

    • Default: 0
    • Purpose: Enable support for contiki_argc / contiki_argv.

  • WITH_PFS

    • Default: 0
    • Purpose: Implement the CFS interface with a Platform-specific File System instead of the POSIX file system.