S42/Central Software User Guide
1VV0301318 Rev. 3
– 2018-08-31
Reproduction forbidden without written authorization from Telit Communications S.p.A.- All Rights Reserved.
Page 32 of 66
4.
Startup Timing
The start-up time until the S42/Central is able to accept link requests or serial data
depends on:
•
the firmware version
•
the source for the slow clock
•
the usage of the UART Interface Control Protocol (UICP)
For more details about the UICP protocol please refer to the document
UICP+ UART Interface Control Protocol
.
4.1.
Firmware Version 3.002
The following diagram shows the startup timing of the S42/Central
based on firmware version 3.002 with external 32,768 kHz crystal signal and UICP deactivated.
(*) The firmware is command ready ~840ms after the reset has been released and when GPIO8
(IOA) is low.
After GPIO8 gets low the state of the /RTS and /IUR-OUT lines depends on the UICP
parameter. When UICP is disabled (AT+UICP=0) both output lines get low, otherwise
the UICP function will be started.
For more details about the UICP protocol please refer to the document
UICP+ UART Interface
Control Protocol
.