User's Manual

User Manual
SM3000 OEM module
If the DTR is pulled high before the end of the message the module will stop transmission and considers the
message lost (message is thrown away).
Please refer to Section Timing for timing values. After lowering the DSR the module will wait for maximum
T
1
(host response time) for the host to lower its DTR line. If this time is exceeded the module will raise its
DSR line and consider the message lost (message is thrown away)
After lowering the DTR line the host should receive a complete message within T
2
. If this is not the case the
host can raise its DTR line and disable its receiver until the module generates a new negative edge on the
DSR line.
In case the host is always on (e.g. a PC) and needs no wake-up mechanism, implementation of the interface
can be simplified by pulling the DTR line low continuously and ignore the DSR line (see also: Remarks –
Host implementationWin32)
Parallel execution
Please note that both module and host should support parallel execution of sending and receiving. It is for
example possible that the module after lowering its CTS starts a transmission by pulling its DSR line low.
The host should be able to accept this request and start receiving data in parallel to its active transmission.
Timing
The following section specify the timing characteristics of the interface
Host to SM3000
18/27 Ambient Systems B.V.