Remove imm.4, merged with vpo.4

Fix vpo.4 manpage generation in Makefile
Fix bootflags bits description in ppc.4

1 files changed, 20 insertions, 0 deletions

diff --git a/share/man/man4/ppbus.4 b/share/man/man4/ppbus.4
index 74a06bd..3b012f4 100644
--- a/share/man/man4/ppbus.4
+++ b/share/man/man4/ppbus.4
@@ -155,6 +155,26 @@ DMA as well as programmed I/O for the host register interface.
 The EPP protocol was originally developed as a means to provide a high
 performance parallel port link that would still be compatible with the
 standard parallel port.
+.Pp
+The EPP mode has two types of cycle: address and data. What makes the 
+difference at hardware level is the strobe of the byte placed on the data
+lines. Data are strobed with nAutofeed, addresses are strobed with 
+nSelectin signals.
+.Pp
+A particularity of the ISA implementation of the EPP protocol is that an 
+EPP cycle fits in an ISA cycle. In this fashion, parallel port peripherals can
+operate at close to the same performance levels as an equivalent ISA plug-in
+card.
+.Pp
+At software level, you may implement the protocol you wish, using data and
+address cycles as you want. This is for the IEEE1284 compatible part. Then,
+peripheral vendors may implement protocol handshake with the following 
+status lines: PError, nFault and Select. Try to know how these lines toggle
+with your peripheral, allowing the peripheral to request more data, stop the
+transfer and so on.
+.Pp
+At any time, the peripheral may interrupt the host with the nAck signal without
+disturbing the current transfer.
 .Ss Mixed modes
 Some manufacturers, like SMC, have implemented chipsets that support mixed
 modes. With such chipsets, mode switching is available at any time by