User's Manual

Bluetooth Transmit Data Module
Shanghai Ehong Technologies Inc
6. PIO
EH-MA41 has a total of 10 digital programmable I/O terminals. They are powered from VDD
(3.3V). Their functions depend on firmware running on the device. PIO lines can be configured
through software to have either weak or strong pull-ups or pull-downs.
Note:
All PIO lines are configured as inputs with weak pull-downs at reset.
Any of the PIO lines can be configured as interrupt request lines or as wake-up lines from sleep modes.
7. AIO
EH-MA41 has 2 analogue I/O terminals. Their functions depend on software. Typically ADC
functions can be configured to battery voltage measurement. They can also be used as a digital
PIO.
8. UART
This is a standard UART interface for communicating with other serial devices. The UART
interface provides a simple mechanism for communicating with other serial devices using the
RS232 protocol.
The UART CTS and RTS signals can be used to implement RS232 hardware flow control where
both are active low indicators.
Table 8: Possible UART Settings
9. I2C Master
PIO6, PIO7 and PIO8 can be used to form a master I
2
C interface. The interface is formed using
software to drive these lines. It is suited only to relatively slow functions such as driving a LCD,
keyboard scanner. In the case, PIO lines need to be pulled up through 2.2K
Ω
resistors.
Parameter Possible Values
Baud Rate
Minimum
1200 baud (≤2%Error)
9600 baud (≤1%Error)
Maximum 3M baud (≤1%Error)
Flow Control RTS/CTS or None
Parity None, Odd or Even
Number of Stop Bits 1 or 2
Bits per Byte 8