Bridgeboards & Emulator Cards

ID #3151

ML Tomlinson: Crosslink

Connection: ISA, Zorro II

Crosslink
Crosslink

Closeup of Crosslink
Closeup of Crosslink

Hi Res Version, Crosslink - 197K
Hi Res Version, Crosslink closeup - 312K

Only a handful of these cards were ever made, perhaps as few as 20. The CrossLink is a bridgeboard with a difference, unlike most other bridgeboards, this card is not an emulator but actually makes the ISA slots found in most big box Amiga's active. That is, you can use real ISA cards on the Amiga, providing that there is a driver available and they don't use DMA. Unfortunately the ISA specifications requires a real X86 processor in order to do DMA, which obviously the Amiga does not have. It also contains an IDE hard drive interface and two serial ports on board. Real ISA cards can also be used under the software PC emulator called CrossPC.

Supported features

- 8 and 16 bit access to the 1K I/O and 1M memory space.
- Wait states for slow boards.
- system clock and 14MHz clock.
- Full interrupt support with custom on-board interrupt controller.
- Only uses 64K Amiga memory space. Doesn't reduce the amount of memory you can add to your Amiga.

A ROM is installed on the CrossLink card which contains the xlink.resource, and a device driver to enable booting directly from an IDE hard drive (xlide.device). Installation consists mainly of plugging the CrossLink card into one of the "bridge" slots in your mother board. That is, one of the slots which has both the Amiga Zorro connector and the IBM PC-AT bus connector in line. There is no need to set any jumpers on the card. The IDE drive and serial ports are automatically detected if present. The devs directory on the supplied disk contains some device drivers which you should copy into your devs: directory. These are:

xlser.device                     serial device driver
networks/xl_ne1000.device NE 1000 ethernet card driver
networks/xl_ne2000.device NE 2000 ethernet card driver

The device driver for the IDE interface (xlide.device) is in the ROM on the card.

IDE drive

Features:
- Autobooting
- Uses standard RDB format (if using HD-ToolBox, simply add the tooltype SCSI_DEVICE_NAME=xlide.device)
- Can use an MFM/RLL 16 bit controller instead of the IDE interface [lowlevel command supplied to low-level format drive(s)]
- Supports two controllers with a maximum of two drives per controller.

Jumpers are available to change the drive to the secondary address. JP1 changes the address, JP2 and JP3 control the interrupt number to use. As shipped, the onboard controller is set to the secondary address and IRQ15. This allows a standard IDE or MFM/RLL controller to be plugged into the bus without any changes made. For reference, the IDE port uses addresses $1F0-$1F7. The secondary port uses addresses $170-$177. The drives on the onboard controller are unit numbers 0 and 1. A plug-in card at the primary address appears at units 2 and 3. Most IDE drives can support multiple sector transfers, which can speed up drive performance. A utility "setmult" has been provided to enable this mode of transfer. Simply put "setmult " somewhere in yourstartup-sequence to enable this. MFM/RLL controllers and some older IDE drives don't support this, and an error will be returned from setmult. A good high speed IDE drive can achieve better than 1.5MB/sec transfer rate with multiple transfers enabled.

Serial Port

Features:
- Two serial ports can be added simply by plugging in two 8250, 16450 or 16550A UART chips.
- Automatically detects 16550A's and uses their FIFO's.
- Emulates the serial.device protocol with xlser.device.
- Currently can drive 10 serial ports simultaneously.

If you only install one of the two onboard serial ports, it must be Unit 0 (i.e. the lower UART).Each serial port must have its own separate interrupt, and be mapped to a different I/O address. The xlser.device automatically detects which COM ports are connected to which interrupt lines. The I/O addresses are listed below:

Unit No.      I/O address    Int number (*)
0 $0F0 10 lower onboard port
1 $0F8 11 upper onboard port
2 $3F8 4 COM 1
3 $2F8 3 COM 2
4 $3E8 2 COM 3
5 $2E8 5 COM 4
6 $3D8 --
7 $2D8 --
8 $3C8 --
9 $2C8 --

(*) These numbers are recommended numbers only. As stated above, the device driver automatically detects which interrupts the ports are connected to. Units 0 and 1 are hardwired, however. If you have a PC card which does not let you set the interrupts uniquely, then you will be unable to use those two serial ports simultaneously.

For reference, here is the pinout of the 9pin and 25pin RS-232 connectors:

Name          9 pin       25 pin
TxD 3 2
RxD 2 3
RTS 7 4
CTS 8 5
DSR 6 6
GND 5 7
DCD 1 8
DTR 4 20
RI 9 22

Ethernet Card

Drivers for the NE1000 and NE2000 compatible cards are in the devs directory on the disk. Please note that these drivers are SANA-II drivers, and will work with applications such as AmiTCP. At least Workbench 2.04 is required in order to use these drivers.

Contributions to this page by:
Dean Thompson, Simon Noble

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Last update: 2009-01-25 14:19
Revision: 1.0

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