>Date: Tue, 16 Jun 1998 05:52:20 GMT >Reply-To: pic microcontroller discussion list >From: Nowhere Man >Subject: Re: [OT] X-modem protocol >To: PICLIST@MITVMA.MIT.EDU > >Remember also that the 'window size' is 1. An ACK must be sent to the >sender before the next packet will be sent. If the checksum doesnt >match, a NAK must be sent. After 10 NAKs, the transfer should abort. >Take a look through: >http://oak.oakland.edu/pub/misc/protocols/ > Specifically the protocol.doc and ymodem8.doc files. They provide a >mode verbose description of the protocols. > >Paul > >On Mon, 15 Jun 1998 23:05:03 -0700, you wrote: > >>X-Modem: >> >>Offset Contents >>0 SOH =3D Ascii 01 >>1 Block #, start with 1, wrap to 0 after FF >>2 Ones complement of block # >>3-130 128 bytes of data >>131 Checksum of bytes (carry ignored) >> >>Best regards- >>John >>-----Original Message----- >>From: Matt Bonner >>To: PICLIST@MITVMA.MIT.EDU >>Date: Monday, June 15, 1998 6:34 PM >>Subject: [OT] X-modem protocol >> >> >>>I've been searching, but can't find much on this. >>> >>>Does anyone have a description (flow-chart, algorithm, etc) of the >>>Xmodem protocol? I prefer the Xmodem-1K version (sometimes called >>>Ymodem) since it supports CRC instead of checksum error detection. >>> >>>--Matt >>> > ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com