User's Manual

page 24/51
HiAll
NC
User Manual 2012/06/28
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Avoid supplying power to the main UART before the HiAll
NC
is ON, as this may result in power up
sequence error.
3.5.2 Complete V24 interface with PC
It supports speeds up to 1Mbps (115.2 Kbps with auto bauding).
To use the V24 interface, some level shifter components are necessary, as HiAll
NC
signals need to be converted
to +/- 5V signals compatible with a PC.
Figure 17: Connection to a data cable
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Avoid supplying the UART before HiAll
NC
module is ON, as this could result in power up sequence error.
To create your own data cable (for software download purpose…etc…) refer to the following schematic as an
example with a MAX3238E:
• VCC_3V1 is an LDO output (VBAT to VCC_3V1) enabled by VGPIO from the module. Yet it can be any
voltage between 3V and 5V (see MAX3238E or MAX3237E specification).
• 180Ω are serial resistors aimed to limit the EMC and ESD propagation.
• Additional voltage level translator must be added to the design when GPIO of HiAll
NC
module was set to
1.8V mode.