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Text File | 1994-08-17 | 16.2 KB | 482 lines

Block Driver Specification -------------------------- Hugo Fiennes, Rev 10a, 17th August 1994 Contact me on 0749 670058 (altman@cryton.demon.co.uk, fidonet 2:255/102.0) for information about the latest version of the spec. Aim --- To provide a standard way for applications to access serial devices. Any application supporting block drivers can be used with many serial devices, with no modification required to the application code - and it's easier to use than the serial SWIs anyway! Info ---- This standard is public domain. The drivers supplied are freely distributable but © 1994 Hugo Fiennes of The Serial Port. If you intend to use the block drivers, please distribute the whole block driver package (inc sample source, this file, and the complete !SerialDev application) with your program, making sure that you are distributing the latest version (available from The World of Cryton BBS, Arcade BBS, and ftp.demon.co.uk in the /pub/archimedes directory). An application called !SerialDev holds the drivers - in your application !Run sequence you should check to see if <SerialDev$Path> is set, and if not, set it to your application directory, inside which is Modules.Internal at least, for your application to default to the internal port. Eventually the idea is to have !SerialDev hold an application that handles the installation in a 'pretty way' - eg dragging new drivers to a window to install them, this would check to see if the driver was a later version of an existing driver and if so replace the old one, otherwise it would install the driver. Maybe this application could look a bit like ArtWorks !FontInst. Hint, hint, somebody write one... The drivers each have their own directory just in case, possibly extensions with !Run files, modules, etc relating to the driver could be stored there. Of course, drivers know their own name and could load files into RMA on initialisation now and cause no problems. ARCterm 7 1.44 and later use drivers of this specification. In this archive I have included some other drivers, documented below. Other programs that support block drivers are: Binkleyterm (2.11+), Hearsay 2 (2.17+), ARCfax (1.06+), ARCbbs (1.63+), RISCbbs (1.02+), Netway. C headers have been provided for C programmers. BASIC/Assembler people should have no problems working it out either - a small application, 'Example' is provided which will work with any block driver module to provide a very simple terminal program. REVISION 4 : Added 'wont empty' and 'dont overlay io' flags for pipes and (unfixed) RO3.10 serial ports. REVISION 5 : Intialise can now return an error string. REVISION 6 : More information on calling initialise. REVISION 7 : Pipe drivers now support 'peek byte' - return next byte in buffer without removing it. REVISION 8 : Internal port with PC cable now works with DCD low (bit 1 on SerialOp 0 now set). OSBYTE 152 used for peek byte (for some reason the proper legal method doesn't work well). REVISION 9 : All drivers must now store R14 on the stack so they can be called from supervisor mode. REVISION 10: Basically this release just tidied the internal driver for RiscPC use - hitting the metal isn't required anymore to set high rates, so it isn't done. Still needed on A5000, A3010, A3020, A4000 & A4 though. Inquiry initialise (see below) added for JP :-) This is implemented in Internal, SP_Dual and Pipe drivers. It's only really necessary in the Internal (sets baud tables) and the SP_Dual (counts installed ports) drivers. REVISION 10a:"I must not release software without testing it" :-) A little buglet in the SP_Dual drivers was pointed out to me, "they don't work!". This has now been fixed. Drivers should now also preserve the PSR (Internal, Dummy, Pipe, and SP_Dual do) just in case. Internal driver --------------- There are two version of this: Internal and InternalPC - the PC version expects a standard PC serial cable, which will only work properly on A5000 or later machines (some early A5000s might have problems too). Needs RO3.1 for block operations. On a 'new hardware' machine (ie A5000 or later) will support 38400, 57600, 115200 automatically. Remember that these rates may well not be reliable due to the lack of FIFO on the serial chip. These rates are acheived by writing directly to the serial chip, which is definitely not Acorn-approved. Beware! On RiscPCs all rates to 115200 should be perfectly reliable as the hardware now includes a FIFO. Cables - the Acorn wiring for a modem is this: Acorn 9w female Modem 25w male --------------- -------------- 1-4-8 20 2 3 3 2 5 7 6 5 7 4 9 8 And the PC wiring is this: Acorn 9w female Modem 25w male --------------- -------------- 1 8 2 3 3 2 4 20 5 7 6 6 (not usually used much) 7 4 8 5 9 22 (not usually used much) Serial Port Dual Serial ----------------------- Again, there are 2 versions: SP_Dual and SP_DualPC, the PC version expects a standard PC serial cable. Since release 9, the Xon/Xoff flags are cleared every time flow control is changed to stop things sticking if an Xoff has been received. PipeA and PipeB --------------- This will autoload the ARCbbs_Pipes module (contained in the PipeA directory) if necessary. The idea is, you open a port (0-15) on pipeA and data sent appears in the input of the corresponding port on pipeB (and vice-versa). DTR at one end is translated to DCD at the other (ditto for RTS-CTS). In this way, any application which supports the block driver spec can talk to another, for example, with ARCbbs and the ARCterm modem server on the same machine, some ARCbbs ports could be given over to network access via the modem server. The pipes use the flag 'wont empty' as you can't wait for the pipe to 'finish sending' as the other end of the pipe may be waiting for the same thing (unlike a serial port, where the data will go away eventually). The pipes are 2k long in each direction. Acorn Telnet (Needs Acorn's TCP/IP protocol suite) ------------ *Note! Does not store R14_SVC This is only in testing, but is supplied as it might be useful. The coding is possibly quite inefficient, but it works. You require !Internet and !Telnet to have been run before trying to use the driver. It will prompt for a host name - type one, or an internet address. You can add ',xx' where xx is the port number to telnet into. DCD as reported by modem status will go high when a sucessful connection is made. Dropping DTR then raising it again will clear any current call. Known bugs: You can't have multiple sessions - if you load another emulator and run telnet the port_claim message will stop the first one - possibly a 'dynamic' port number (returned by init?) should be put into the spec to cater for things like this. Dummy (/dev/null) ----- This is a dummy driver, for when you want somewhere to trash data. It always shows CTS, DSR and DCD, and will completely ignore any data you send to it. It never has any data to give you. II_Dual driver -------------- *Note! Does not store R14_SVC This is a temporary stop-gap until v3.xx software is available for the II card. The port number you specify is the II port number -1, ie II port 3 would be specified as port 2. If you want to use the internal port while using II ports, you need the Internal2 driver. Both of these drivers rely on the poll entry being called directly after each wimp poll, to set the current port. Econet driver (not supplied with this release) ------------- This works with ARCterm's new 16-line modem server to allow remote serial access. To support connection, etc, it has 3 special functions: Connect (function code 128) r1=handle/net/station (handle in bits 16-23,net in bits 8-15, station in 0-7) r2-> password, null terminated Tries to set up a connection with the modem server. Returns 0 for success, 1 for no reply, 2 for already connected, or a pointer to an error block if r0 is 'big' on return. Disconnect (function code 129) Disconnects from the modem server. Scan for modem servers (function code 130) r1=buffer to fill of format: 0 station 1 net 2 handle 3 modem driver number as defined in the modem server config file 4-63 modem ID string (null terminated) r2=max number of entries table can handle ------------------------------------------------------------------------------- Driver layout ------------------------------------------------------------------------------- 0x000 Entry point to call routines In: r0=function code r1-r3=data Out: r0=result NOTE! CHANGE IN REVISION 9! | | This entry point can be called in EITHER user or supervisor mode, so | R14 should always be pushed on the stack (STMFD R13!,{R14}) and be used | to return from the driver so that r14_svc is preserved if the driver is | called when in supervisor mode. | r0-r3 can be corrupted, r4-r12 should be preserved. r14 contains the return address Callers note that r13 should point to a full, descending stack with a decent amount of space free on it. Example handler code follows: entry STMFD R13!,{R14} CMP R0,#((endoftable-table)/4) ADDCC PC,PC,R0,LSL#2 LDMFD R13!,{PC} table B func_0 B func_1 endtable 0x080 Driver information string (31 bytes max, 0 terminated) 0x0A0 Manufacturer information string (31 bytes max, 0 terminated) 0x0C0 Version number (top 16 bits major, low 16 bits minor) 0x0C4 Driver flags 0x00000001 - More than one port availiable 0x00000002 - Supports split rates 0x00000004 - Has >1 byte hardware FIFO 0x00000008 - Can use Set control lines to generate a break 0x00000010 - Requires polling (by function 19) 0x00000020 - Won't empty (is a shared buffer) 0x00000040 - Supports block get/put operations 0x00000080 - Prefer not to overlap serial IO and disk IO 0x00000100 - Supports inquiry initialise 0xdd...... - Top byte is highest port number supported (numbered from 0) 0x0C8 Driver number. This is allocated by me, and always has the lowest byte as 0. The purpose of the driver number is for the Device_Claim protocol: when a serial port is specified, the port number is used to specify which port is to be claimed/released. The internal port is port 0 and driver number 0. To make the port number to use you add the sub-port number and the driver number together. eg, say the II dual card was driver number 1 (0x00000100) and you wanted to claim port 5, you would use the port number 0x00000105. This is unique and hopefully would cause no problems. PORT NUMBERS PASSED TO BLOCK DRIVERS ARE THE LOWER 8 BITS ONLY: THEY DO NOT INCLUDE THE DRIVER NUMBER. Currently allocated driver numbers: 0 - Internal serial 1 - II dual serial 2 - Serial port dual serial 3 - Internal serial with PC cable 4 - Brainsoft Multipod (Kelvin Hill, #179 on Cryton) 5 - Acorn telnet interface 6 - Serial port dual serial with PC cable 100 - Remote econet driver 128 - Virtual pipe (end A) 129 - Virtual pipe (end B) 0x0CC - 0x0FF reserved 0x100 Supported speed table. One word per speed, terminated with a null word. 0x180-> driver code. Function codes -------------- r0=0 Put byte -------- r1=port number r2=byte to send Returns with r0=-1 if byte not inserted, r0=0 if byte inserted into TX queue. r0=1 Get byte -------- r1=port number Returns with r0=-1 if no byte availiable, r0=byte if a byte was removed. r0=2 Put block --------- r1=port number r2=pointer to block r3=number of bytes to try and insert Returns with r0=number of bytes sucessfully inserted. r0=3 Get block --------- r1=port number r2=pointer to block r3=maximum number of bytes to put into buffer Returns with r0=number of bytes put in buffer. r0=4 Check TX buffer --------------- r1=port number Returns with r0=number of bytes free in TX buffer r0=5 Check RX buffer --------------- r1=port number Returns with r0=number of bytes used in RX buffer r0=6 Flush TX buffer (and hardware FIFO if applicable) --------------- r1=port number r0=7 Flush RX buffer (and hardware FIFO if applicable) --------------- r1=port number r0=8 Control lines ------------- r1=port number r2=-1 to read or new settings Returns r0=control line settings b0=DTR b1=RTS b2=If set, set TX data active (ie break state) r0=9 Read modem control lines ------------------------ r1=port number Returns r0=control line status b0=CTS b1=DSR b2=RI b3=DCD r0=10 Read RX errors -------------- r1=port number Returns r0=bitset of errors seen since last read RX errors. b0=Overrun error b1=Parity error b2=Framing error b3=Break received r0=11 Send break ---------- r1=port number r2=break time (in centiseconds) This does not return until the break has been sent - although some serial ports could multitask when sending a break, the internal port can't. Check the driver flags to see if you can use a multitasking break before using this call. r0=12 Examine byte (like Get byte but leaves it in the buffer) ------------ r1=port number Returns with r0=-1 if no byte availiable, r0=byte if a byte was returned. r0=13 TX Speed -------- r1=port number r2=speed to set or -1 to read Returns with r0=speed. r0=14 RX Speed -------- r1=port number r2=speed to set or -1 to read Returns with r0=speed. r0=15 Set word format --------------- r1=port number r2=word format to set or -1 to read Returns with r0=word format. r0=16 Set flow control ---------------- r1=port number r2=flow control method to set or -1 to read Returns with r0=method 0=no flow control 1=hardware 2=xon/xoff 3=both r0=17 Initialise driver ----------------- r1=port number r2=parameter string (optional) r2 optionally points to a null terminated string which can specify device options. Returns with r0 pointing to error string if initialisation unsucessful, otherwise r0=0. NOTE! Do not read the baud rate tables or driver flags UNTIL AFTER the intialise driver entry has been called. This allows for drivers to configure themselves to the available hardware and adjust the services offered accordingly. Release 10: There is now a flag, 'supports inquiry initialise' (see above) which allows you to call the initialise entry with r1=-1, which will not touch any hardware, just set all the baud tables, driver flags, and count the number of ports installed (if necessary), so you can read them and set up menus, etc. r0=18 Close down driver ----------------- r1=port number r0=19 Poll driver ----------- r1=port number This should be called regularly (eg in a polling loop) for the driver to perform polling tasks - eg the econet driver needs to check internal buffers and poll econet protocol tasks. Polls can be as infrequent as three or four times a second : if a driver needs polling more often than that, it should install a module and hook onto a vector somewhere.