S42 Hardware User Guide
Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights Reserved.
Page 19 of 62
Pin Name
State: S42
EXT-RES#
Input with pull-up
(1)
XL-IN
Input floating (disconnected)
XL-OUT
Input floating (disconnected)
UART-TXD
Input floating (disconnected)
UART-RXD
Input floating (disconnected)
UART-RTS#
Input floating (disconnected) with pull-up resistor 470k
Ω
(2)
UART-CTS#
Input floating (disconnected)
IUR-OUT#
Input floating (disconnected)
IUR-IN#
Input floating (disconnected)
GPIO[0:14]
Input floating (disconnected)
TESTMODE#
Input floating (disconnected)
BOOT0
Input floating (disconnected)
SWDIO
Input with pull-up
(1)
SWCLK
Input with pull-down
(1)
(1)
pull-up, pull-down: R
PU,
R
PD
is typ. 13k
Ω (11kΩ to 16kΩ)
(2)
a discrete resistor is used
Table 3: Pin States during Reset
The pin states as indicated in Table 3 are kept until hardware initialization has started.
3.3
Serial Interface
The serial interface of S42 is a high-speed UART interface supporting RTS/CTS
flow control and interface-up/down mechanism according to the UICP+ protocol (refer to
UICP_UART_Interface_Control_Protocol, 30507ST10756A). Electrical interfacing is at
CMOS levels (defined by VSUP; see chapter 5.4.1).
Transmission speeds are 9600 – 921600 bps and 1Mbps (asynchronous)
Character representation: 8 Bit, no parity, 1 stop bit (8N1)
Hardware flow-control with RTS and CTS (active low)
NOTE:
Transmission speed may be limited by firmware. See corresponding command reference
Reference for further information.