User`s manual
BL160044 s System Development
If the device with which the BL1600 is communicating does not support
CTS and RTS, the CTS and RTS lines on the BL1600 side can be tied
together to make communication possible.
The CTS line (/CTS0) is grounded when not in use.
XMODEM File Transfer
The BL1600 supports the XMODEM protocol for downloading and
uploading data. Currently, the library supports downloading an array of
data whose size is a multiple of 128 bytes.
Uploaded data are written to a specified area in RAM. The targeted area
for writing should not conflict with the current resident program or data.
Character echo is automatically suspended during XMODEM transfer.
Modem Communication
Using modems and telephone lines allows RS-232 communication across
great distances. If you choose the modem option, character streams that
are read from the receive buffer are automatically scanned for modem
commands. When a modem command is found, the software takes
appropriate action. Normally, the communication package would be in
COMMAND mode while waiting for valid modem commands or mes-
sages. Once a link is established, communication is in DATA mode
(regular RS-232). However, the software continues to monitor the modem
for a NO
_
CARRIER message.
The software assumes that modem commands are terminated with CR,
that is, a carriage return (0x0D). The modem option is easiest to use when
the user protocol also has CR as the terminating character. Otherwise,
the software has to check for two different terminating characters. The
users terminating character cannot be any of the ASCII characters used in
modem commands nor can it be a line-feed character.
The RS-232 library supports communication with a Hayes Smart Modem
or compatible modem. The CTS, RTS and DTR lines of the modem are
not used. If the modem used is not truly Hayes Smart Modem compatible,
the CTS, RTS and DTR lines on the modem side need to be tied together.
The CTS and RTS lines on the BL1600 side also have to be tied together.
A NULL connection is also required for the TX and RX lines. A commer-
cial NULL modem would already have its CTS and RTS lines tied together
on both sides.