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— | base:rr-net_memory_map_docs [2015-04-17 04:33] (current) – created - external edit 127.0.0.1 | ||
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+ | ====== RR-net memory map & docs ====== | ||
+ | < | ||
+ | This document is freely distributable as long as it is not changed, and one | ||
+ | of the sources www.jschoenfeld.com, | ||
+ | or www.ami.ga is mentioned. | ||
+ | last update: | ||
+ | august 31st, 2003: initial release | ||
+ | |||
+ | General | ||
+ | ------- | ||
+ | RR-Net is a 10MBit networking card that is designed for the commodore C64, | ||
+ | for use on the Retro Replay freezer cartridge. It'll also work on the Amiga | ||
+ | with a clock-port, but it is not recommended: | ||
+ | and it hardly fits mechanically. If you need network for your Amiga, use the | ||
+ | X-Surf 2 board. | ||
+ | |||
+ | Memory map | ||
+ | ---------- | ||
+ | The memory map depends on the place where RR-Net is connected. Although | ||
+ | RR-Net is designed for the C64, here are also the offset addresses for the | ||
+ | Amiga. Check the corresponding hardware documentations for the carrier cards | ||
+ | to obtain the base addresses of the clockport. | ||
+ | |||
+ | RR-Net is based on the Cirrus logic CS8900a (Crystal LAN). The chip is used | ||
+ | in 8-bit mode, so the 8 registers of an NE2000 are spread over 16 registers | ||
+ | in an 8-bit system. The 8-bit mode of the chip does not support IRQs (see | ||
+ | Cirrus logic application note AN181). | ||
+ | |||
+ | Do not forget to switch on the accessory connector of the Retro Replay by | ||
+ | setting bit 0 in $de01. See Inside_Replay.txt for more information. | ||
+ | |||
+ | C64 register | ||
+ | none $00/ | ||
+ | $de02/ | ||
+ | $de04/ | ||
+ | $de06/ | ||
+ | $de08/ | ||
+ | $de0a/ | ||
+ | $de0c/ | ||
+ | $de0e/ | ||
+ | |||
+ | Although the Amiga makes the interrupt status queue registers available, it | ||
+ | does not have any effect. Even if you try to activate the chip's IRQ features, | ||
+ | it will not have any effect. The IRQ line of the chip is not wired on RR-Net | ||
+ | at all! | ||
+ | If you compare this register map to the register map in AN181, you might | ||
+ | notice that the first and the second half of the register set is swapped. | ||
+ | This has been done, because the accessory connector of the Retro Replay does | ||
+ | not provide the full range of registers available on the Amiga clockport. The | ||
+ | first two bytes are control registers of the freezer cartridge, and this | ||
+ | swapping moves the unnecessary register-pair (IRQ status queue) into the | ||
+ | " | ||
+ | |||
+ | Endianess | ||
+ | --------- | ||
+ | Although the chip is used in 8-bit mode, you have to know the endianess, | ||
+ | because each register pair forms a one 16-bit register. Ethernet is | ||
+ | big-endian by default. The chip was designed as an ISA thing, so all | ||
+ | registers appear as little endian. In other words: The lowbyte comes first, | ||
+ | then the highbyte. | ||
+ | |||
+ | MAC address | ||
+ | ----------- | ||
+ | RR-Net does not have an EEprom to store the MAC address, so it should be | ||
+ | stored somewhere else: The flash rom of Retro Replay, the disk of the | ||
+ | Contiki operating system by Adam Dunkels (http:// | ||
+ | or Kickflash OS4 for the Amiga. The Mac address is only needed when | ||
+ | transmitting packets, so it's OK if it's loaded from mass storage media when | ||
+ | loading/ | ||
+ | just connected to other networking equipment. The LINK led might already be | ||
+ | on, but the MAC address is only needed when something is transmitted into the | ||
+ | network. | ||
+ | |||
+ | More literature | ||
+ | --------------- | ||
+ | Cirrus Logic Application note AN181: "Using the Crystal CS8900A in 8-bit | ||
+ | mode" by James Ayres: http:// | ||
+ | |||
+ | Crystal LAN CS8900A Ethernet Controller Technical Reference manual AN83: | ||
+ | http:// | ||
+ | |||
+ | The product data sheet for the CS8900A also contains software information, | ||
+ | starting at chapter 4 (page 38): | ||
+ | http:// | ||
+ | |||
+ | Application note 194: "How to program the Hash filter in the CS8900A": | ||
+ | http:// | ||
+ | |||
+ | The FAQ about the chip: http:// | ||
+ | |||
+ | Fine print | ||
+ | ---------- | ||
+ | RR-Net is not designed, authorized or warranted to be suitable for use in | ||
+ | life-support devices or systems or other critical operations. Inclusion of | ||
+ | the product in such applications is understood to be fully at the | ||
+ | customer' | ||
+ | |||
+ | ** EOF | ||
+ | </ |
base/rr-net_memory_map_docs.txt · Last modified: 2015-04-17 04:33 by 127.0.0.1