User's Manual

User Manual
SM3000 OEM module
Read command
The module will periodically check if the host has any data to send and start communication if so
1
.
The host signals the module it has data to send by pulling the RTS line low. In due time the module lowers
the DR line to mark start of communication.
The module will generate a clock signal on the SCLK line. The clock signal consists of groups of 8 pulses.
Each group represents one byte transmitted and received.
The first byte that is outputted on the MOSI line by the module is the read command: 0x53. For the second
byte the host must then output N: the number of bytes it will send. The module will then generate a clock
signal for N bytes. The host must put its data on the MISO line. The module may put any data on the MOSI
line. These values can be ignored by the host. When all bytes are sent the module raises the DR line again to
mark end of communication.
1 The SM3000 features a wake-up on RTS mechanism. If the SM3000 is in energy saving sleep mode, a downward flank on the RTS
line will wake it up and the module will respond typically within a couple of milliseconds
11/27 Ambient Systems B.V.