User's Manual

BT900-Sx Hardware Integration Guide
Intelligent BTv4.0 Dual Mode Module
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15 CONN-HIG-BT900
R
ext
: Output impedance of external circuit (kOhms)
R
ext
: Sampling time (nS)
T
s
≥ (R
AIN
+ R
ext
) x C
AIN
x 9
R
AIN
: Input resistor of ADC(kOhms)=2.2kOhms at 2.7V≤AVCC≤3.6V
Input resistor of ADC(kOhms)=5.5kOhms at 1.8V≤AVCC≤2.7V
C
AIN
: Input capacity of ADC(pF)=9.4pF at 1.8V≤AVCC≤3.6V
3.3.3 nAutoRUN pin and Operating Modes
Operating modes (refer to the smart BASIC manual for details):
 Self-contained mode
 Interactive / Development mode
Table 7: nAutoRUN pin
Signal Name Pin No
I/
O
Comments
nAutoRUN 3 I
Input with active low logic.
Operating mode selected by nAutoRun pin status:
If Low (0V), runs $autorun$ if it exists;
If High (VCC), runs via at+run (and “file name” of application).
Pin 3 (nAutoRUN) is an input, with active low logic. In the development board (DVK-BT900-sx) it is
connected so that the state is driven by the host’s DTR output line. nAutoRUN pin needs to be
externally held high or low to select between the two BT900 operating modes:
 Self-contained Run mode (nAutoRUN pin held at 0V).
 Interactive / Development mode (nAutoRUN pin held at VCC).
smartBASIC runtime engine firmware checks for the status of nAutoRUN during power-up or reset.
If it is low and if there is a smartBASIC application named $autorun$ then the smartBASIC runtime
engine executes the application automatically; hence the name self-contained run mode.
3.3.4 OTA (Over the Air) smart BASIC application download
In future release this feature will be available.