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OPENCBM(4) Kernel Interfaces Manual OPENCBM(4) NAME opencbm -- OpenCBM driver for parallel-port X[MA]-1541 cables SYNOPSIS opencbm DESCRIPTION The opencbm driver supports Commodore disk drives connected to the par- allel port using an XM(P)-1541 or XA(P)-1541 cable. Loader Tunables The following loader tunables are used to set driver configuration at the loader(8) prompt before booting the kernel, or they can be stored in /boot/loader.conf in order to automatically set them before booting the kernel. It is also possible to use kenv(1) to change these tun- ables before loading the opencbm driver. cbm.cable Set to 0 or 1 to explicitly select an XM-1541 (0) or XA-1541 (1) type cable. The default value of -1 will attempt to auto- detect the cable type, which only works reliably when cbm.reset is active and the drive is connected and powered on while load- ing the opencbm driver. cbm.hold_clk Set to 0 explicitly to release the CLK line of the bus when idle. The default (1) is to strictly follow C64 behavior, al- ways holding the CLK line. cbm.reset When set to 1 (default), execute a bus reset and wait for re- sponse from the drive while loading the opencbm driver. Set to 0 explicitly to load the driver without having to wait for the bus. In this case, you should also select a cable type explic- ity. FILES The opencbm driver creates the following device node: /dev/cbm Device for communicating with a Commodore disk drive over a parallel-port cable. EXAMPLES To load the driver with a drive connected and powered on, auto-detect- ing the cable type: kldload opencbm To load the driver without issuing a bus reset and selecting an active (XA-1541) cable: kenv cbm.cable=1 kenv cbm.reset=0 kldload opencbm If you want to load the driver at system startup, adding it to kld_list in /etc/rc.conf , it is recommended to disable cbm.reset and explicitly select a cable type in /boot/loader.conf , e.g. add the following lines for a passive (XM-1541) cable: cbm.cable=0 cbm.reset=0 SEE ALSO The cables supported by the opencbm driver (XM-1541, XA-1541 and their variations) are described on https://sta.c64.org/xcables.html FreeBSD 14.3 May 27, 2020 OPENCBM(4)
NAME | SYNOPSIS | DESCRIPTION | FILES | EXAMPLES | SEE ALSO
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