User's Manual

page 25/51
HiAll
NC
User Manual 2012/06/28
Figure 18: Example of a connection to a data cable with a MAX3238E
3.5.3 Partial V24 (RX-TX-RTS-CTS) connection of HiAllNC to host
When using only UART1_RXD/ UART1_TXD/ UART1_RTS/ UART1_CTS instead of the complete V24 link, the
following schematic could be used.
Figure 19: Partial V24 connection (4 wires) of HiAll
NC
to host processor
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As UART1_DTR is active (low electrical level) once HiAll
NC
is switched on, UART1_DSR is also active
(low electrical level), therefore the AT command AT+KSLEEP can switch between the two sleep modes.
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UART1_DCD and UART1_RI can remain disconnected and floating when not in use. Otherwise use
100KΩ to pull up to power.
This configuration allows use of flow control UART1_RTS & UART1_CTS to avoid overflow error during data
transfer. Moreover UART1_RTS is used to indicate when the HiAll
NC
module is ready to receive an AT