From 4c9de2fb64d0638e6aaffad81d91dc1e431c343a Mon Sep 17 00:00:00 2001 From: jonathan Date: Mon, 23 Feb 1998 19:46:24 +0000 Subject: [PATCH] Fix typo in dz11/dc speed botch: 19200 is actually 19800, not 19600. Explain more fully why DZ/dc devices lose as PPP/slip interfaces. --- share/man/man4/man4.pmax/dc.4 | 77 ++++++++++++++++++++++------------- 1 file changed, 48 insertions(+), 29 deletions(-) diff --git a/share/man/man4/man4.pmax/dc.4 b/share/man/man4/man4.pmax/dc.4 index e9cf2af51451..64c9b5a18871 100644 --- a/share/man/man4/man4.pmax/dc.4 +++ b/share/man/man4/man4.pmax/dc.4 @@ -27,21 +27,20 @@ .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. .\" -.\" $NetBSD: dc.4,v 1.2 1997/10/13 11:23:45 lukem Exp $ +.\" $NetBSD: dc.4,v 1.3 1998/02/23 19:46:24 jonathan Exp $ .\" -.Dd August 6, 1996 +.Dd February 20, 1998 .Dt DC 4 pmax -.Os NetBSD 1.2a +.Os NetBSD .Sh NAME .Nm dc .Nd -dc659,dc7085 DZ11-on-a-chip serial communications interface +dc659, dc7085 DZ11-on-a-chip serial communications interface .Sh SYNOPSIS .Cd "dc0 at ioasic?" .Cd "dc0 at mainbus" .Cd "dc1 at mainbus" .Cd "dc2 at mainbus" -.Cd "dc0 at vsbus" .Sh DESCRIPTION THe .Nm @@ -64,34 +63,54 @@ baseboard devices on the Vaxstation 2000 and 3100. .Pp The .Nm -device is essentially a single-chip clone of the DZ-11. -It has a small input silo shared across all input ports. -Model control lines are present on two of the four ports. -The device does not interrupt on modem transitions; instead, +device is in essence a single-chip clone of the DZ-11. +The DZ-11 hardware design severely constrains performance. +One small input silo is shared across all input ports. +The +.Nm dc +hardware does not interrupt on modem transitions; instead, they are detected via polling. -Only two lines on a baseboard dc7085 have modem control signals; the -other two are wired for a keyboard and mouse. -On some implementations, only partial modem control (sufficent for -Unix dialup) is provided, while others provide full modem control. -Speeds greater than 19200 are not supported. The 19200 speed is rumoured -to actually be 19600, presumably for bug-compatibility with the DZ-11. +Only two lines on a baseboard +.Nm dc +device have any modem control signals; +the other two lines are wired for a keyboard and mouse. + +On some implementations (e.g., Decstation 3100), the hardware does not +bring out modem flow-control signals to the bulkhead. Only modem +carrier transition are provided. This is adequate for Unix dialin +and dialout detection, but without hardware flow control, the +.Nm +device is prone to overruns when used for serial-line protocols. + +The Decstation 5000/200 +.Nm +hardware provides full modem control on +both bulkhead RS-232 ports and is less prone to overrun. +.Sh BUGS .Pp +The 19200 speed on all +.Nm +devices is actually implemented as 19800, +presumably for bug-compatibility with the original DZ-11. +This is a hardware feature and cannot be corrected in software. +Many serial devices at 19200 fail to interoperate with the +.Nm +at its 19800 speed setting. +.Pp +The Decstation 5000/200 can set a bit in the system register +to allow the +.Nm +to run at 38400, but this applies to all four lines and disables +the 19200 speed on all four lines. This feature is not currently supported. +.Pp +The +.Nm +driver should be merged into a single driver supporting the original +DZ-11, DZ-32, and Qbus DZV-11 and DZQ-11 clones. .Sh HISTORY The .Nm driver first appeared in -.Bx 4.4 /pmax. Support for Vax implementations is -.Ud . -.Sh BUGS -The Decstation 5000 can set a bit in the system register -to allow the -.Nm -to run at 38400, but this applies to all four lines and disables -the 19200 speed. This feature is not currently supported. -.Pp -The driver should probably support the original DZ-11, DZ-32, - and Qbus DZV-11 and DZQ-11 clones. - - - +.Bx 4.4 /pmax. This manual page first appeared in +.Nx 1.2 .